PATENT DOCUMENT

Publication Number: US-11747972-B2
Application Number: US-202117498938-A
Country: US
Kind Code: B2

Title: Media-editing application with novel editing tools

Abstract:
Some embodiments provide a media-editing application with novel editing tools. The media editing application provides an in-line precision editor that can be opened in the composite display area. In some embodiments, a selection of an edge between two clips expands a composite lane into two lanes, a first lane and a second lane. The first lane is then used to perform edits to the left side of the selected edge, while the second lane is used to perform edits to the right side of the selected edge. In some embodiments, the first lane shows the additional media content available for the clip on the left side of the edge to include. The second lane shows the additional media content available for the clip on the right side of the edge to include. The additional media content is in the source media file, of which a clip represents a portion.

Claims:
What is claimed is: 
     
       1. A method for creating a media presentation from a plurality of media clips, the method comprising:
 displaying a composite display area for placing media clips to specify the composite media presentation, the composite display area including a timeline that includes a plurality of lanes; 
 displaying a set of media clips in the composite display area by placing each media clip in the set of media clips with correlated additional media content in an individual lane of the timeline, wherein the media clips and correlated additional media content are from individual source files; 
 receiving a single user input comprising a selection of one media clip from the set of media clips in the composite display area, wherein the selected media clip includes different types of media content and each type of media content includes a set of tracks; 
 in response to receiving the single user input comprising the selection of the one media clip, replacing the set of media clips in a visible portion of the plurality of lanes of the timeline with:
 (a) a first set of one or more tracks corresponding to a first type of media content, of the selected media clip, in a first set of one or more of the plurality of lanes; and 
 (b) a second set of one or more tracks corresponding to a second type of media content, of the selected media clip, in a second set of one or more of the plurality of lanes, wherein the timeline does not show any other media clips of the set of media clips subsequent to replacing the set of media clips in a visible portion of the timeline. 
 
 
     
     
       2. The method of  claim 1 , wherein the set of lanes of the timeline comprises a primary lane for placing a primary sequence of media clips and one or more secondary lanes for placing media clips that are anchored to media clips in the primary lane. 
     
     
       3. The method of  claim 2 , further comprising, in response to displaying the set of tracks of the selected media clip in different lanes of the timeline:
 displaying a particular track of a particular media content type of the selected media clip in the primary lane; and 
 displaying other tracks of the particular media content type and other media content types in different secondary lanes of the composite display area. 
 
     
     
       4. The method of  claim 1 , further comprising:
 receiving a user input to trim a first media clip displayed in a particular lane of the timeline; 
 in response to receiving the user input, trimming a beginning of the first media clip displayed in the particular lane; and 
 in response to trimming the beginning of the first media clip, moving a second media clip that is displayed before the first media clip in the particular lane towards the first media clip as the first media clip is being trimmed. 
 
     
     
       5. The method of  claim 4 , wherein the second media clip is moved without adding additional media content of the second media clip to an end of the second media clip closest to the first media clip. 
     
     
       6. The method of  claim 4 , further comprising expanding a region of the timeline that is positioned before the first media clip as the first media clip is being trimmed. 
     
     
       7. The method of  claim 6 , further comprising, in response to completion of the trimming of the first media clip, restoring a size of the region to an original size of the region prior to the expanding. 
     
     
       8. The method of  claim 1 , further comprising:
 trimming a first amount of media content from a first media clip; and 
 incrementing first additional media content for the first media clip by the first amount of media content trimmed off the first media clip. 
 
     
     
       9. A non-transitory machine readable medium storing a media-editing application for creating a media presentation from a plurality of media clips, the media-editing application comprising sets of instructions for:
 displaying a composite display area for placing media clips to specify a composite media presentation, the composite display area including a timeline that includes a plurality of lanes; 
 displaying a set of media clips in the composite display area by placing each media clip in the set of media clips with correlated additional media content in an individual lane of the timeline, wherein the media clips and correlated additional media content are from individual source files; 
 receiving a single user input comprising a selection of one media clip from the set of media clips in the composite display area, wherein the selected media clip includes different types of media content and each type of media content includes a set of tracks; 
 in response to receiving the single user input comprising the selection of the one media clip, replacing the set of media clips in a visible portion of the plurality of lanes of the timeline with:
 (a) a first set of one or more tracks corresponding to a first type of media content, of the selected media clip, in a first set of one or more of the plurality of lanes; and 
 (b) a second set of one or more tracks corresponding to a second type of media content, of the selected media clip, in a second set of one or more of the plurality of lanes, wherein the timeline does not show any other media clips of the set of media clips subsequent to replacing the set of media clips in a visible portion of the timeline. 
 
 
     
     
       10. The non-transitory machine readable medium of  claim 9 , wherein the set of lanes of the timeline comprises a primary lane for placing a primary sequence of media clips and one or more secondary lanes for placing media clips that are anchored to media clips in the primary lane. 
     
     
       11. The non-transitory machine readable medium of  claim 10 , wherein the media-editing application further comprises sets of instructions for, in response to displaying the set of tracks of the selected media clip in different lanes of the timeline:
 displaying a particular track of a particular media content type of the selected media clip in the primary lane; and 
 displaying other tracks of the particular media content type and other media content types in different secondary lanes of the composite display area. 
 
     
     
       12. The non-transitory machine readable medium of  claim 9 , wherein the media-editing application further comprises sets of instructions for:
 receiving a user input to trim a first media clip displayed in a particular lane of the timeline; 
 in response to receiving the user input, trimming a beginning of the first media clip displayed in the particular lane; and 
 in response to trimming the beginning of the first media clip, moving a second media clip that is displayed before the first media clip in the particular lane towards the first media clip as the first media clip is being trimmed. 
 
     
     
       13. The non-transitory machine readable medium of  claim 12 , wherein the second media clip is moved without adding additional media content of the second media clip to an end of the second media clip closest to the first media clip. 
     
     
       14. The non-transitory machine readable medium of  claim 12 , wherein the media-editing application further comprises a set of instructions for expanding a region of the timeline that is positioned before the first media clip as the first media clip is being trimmed. 
     
     
       15. The non-transitory machine readable medium of  claim 14 , wherein the media-editing application further comprises a set of instructions for, in response to completion of the trimming of the first media clip, restoring a size of the region to an original size of the region prior to the expanding. 
     
     
       16. The non-transitory machine readable medium of  claim 9 , wherein the media-editing application further comprises sets of instructions for:
 trimming a first amount of media content from a first media clip; and 
 incrementing first additional media content for the first media clip by the first amount of media content trimmed off the first media clip. 
 
     
     
       17. A system comprising:
 one or more processors; and 
 a non-transitory machine readable medium storing a media-editing application for creating a media presentation from a plurality of media clips, the media-editing application comprising sets of instructions, that when executed by the one or more processors, cause:
 displaying a composite display area for placing media clips to specify the composite media presentation, the composite display area including a timeline that includes a plurality of lanes; 
 displaying a set of media clips in the composite display area by placing each media clip in the set of media clips with correlated additional media content in an individual lane of the timeline, wherein the media clips and correlated additional media content are from individual source files; 
 receiving a single user input comprising a selection of one media clip from the set of media clips in the composite display area, wherein the selected media clip includes different types of media content and each type of media content includes a set of tracks; 
 in response to receiving the single user input comprising the selection of the one media clip, replacing the set of media clips in a visible portion of the plurality of lanes of the timeline with:
 (a) a first set of one or more tracks corresponding to a first type of media content, of the selected media clip, in a first set of one or more of the plurality of lanes; and 
 (b) a second set of one or more tracks corresponding to a second type of media content, of the selected media clip, in a second set of one or more of the plurality of lanes, wherein the timeline does not show any other media clips of the set of media clips subsequent to replacing the set of media clips in the visible portion of the timeline. 
 
 
 
     
     
       18. The system of  claim 17 , wherein the set of lanes of the timeline comprises a primary lane for placing a primary sequence of media clips and one or more secondary lanes for placing media clips that are anchored to media clips in the primary lane, and wherein the media-editing application further comprises sets of instructions that cause, in response to displaying the set of tracks of the selected media clip in different lanes of the timeline:
 displaying a particular track of a particular media content type of the selected media clip in the primary lane; and 
 displaying other tracks of the particular media content type and other media content types in different secondary lanes of the composite display area. 
 
     
     
       19. The system of  claim 17 , wherein the media-editing application further comprises sets of instructions that cause:
 expanding a region of the timeline that is positioned before a first media clip as the first media clip is being trimmed; and 
 in response to completion of the trimming of the first media clip, restoring a size of the region to an original size of the region prior to the expanding. 
 
     
     
       20. The system of  claim 17 , wherein the media-editing application further comprises sets of instructions that cause:
 receiving a user input to trim a first media clip displayed in a particular lane of the timeline; 
 in response to receiving the user input, trimming a beginning of the first media clip displayed in the particular lane; and 
 in response to trimming the beginning of the first media clip, moving a second media clip that is displayed before the first media clip in the particular lane towards the first media clip as the first media clip is being trimmed.

Description:
INCORPORATION BY REFERENCE; DISCLAIMER 
     Each of the following applications are hereby incorporated by reference: application Ser. No. 16/389,639 filed on Apr. 19, 2019; application Ser. No. 13/151,177 filed on Jun. 1, 2011; application Ser. No. 13/151,175 filed on Jun. 1, 2011; application Ser. No. 13/154,361 filed on Jun. 6, 2011; application No. 61/443,702 filed on Feb. 16, 2011; application No. 61/443,704 filed on Feb. 16, 2011; application No. 61/443,707 filed on Feb. 16, 2011; application No. 61/443,692 filed on Feb. 16, 2011; and application No. 61/364,797 filed on Jul. 15, 2010. The Applicant hereby rescinds any disclaimer of claim scope in the parent application(s) or the prosecution history thereof and advises the USPTO that the claims in this application may be broader than any claim in the parent application(s). 
     BACKGROUND 
     Digital graphic design, image editing, audio editing, and video editing applications (hereafter collectively referred to as media content editing applications or media editing applications) provide graphical designers, media artists, and other users with the necessary tools to create a variety of media content. Examples of such applications include Final Cut Pro  and Movie , both sold by Apple, Inc. These applications give users the ability to edit, combine, transition, overlay, and piece together different media content in a variety of manners to create a resulting media project. The resulting media project specifies a particular sequenced composition of any number of text, audio, image, and/or video content elements that is used to create a media presentation. 
     Various media editing applications facilitate such composition through electronic means. Specifically, a computer or other electronic device with a processor and computer readable storage medium executes the media editing application. In so doing, the computer generates a graphical interface whereby designers digitally manipulate graphical representations of the media content to produce a desired result. However, in many cases, the designers experience inconvenience in manipulating graphical representations of the media content because of the shortcomings of the existing applications. Also, it is often not possible to view the desired result until the designers finish manipulating the graphical representation. 
     BRIEF SUMMARY 
     Some embodiments of the invention provide a media-editing application for creating and editing a media presentation that displays the results of edits as the edits are being made to the media presentation. The media-editing application displays the movement of media clips of the media presentation as the media clips are being moved within the media-editing application to change the media presentation. In some embodiments, the media-editing application is an application that enables a user to create a composite media presentation from a set of media clips. Through a graphical user interface (GUI) of the application, the user specifies the manner in which the media clips are composited to create the composite presentation. 
     The media application of some embodiments includes a timeline, which is a composite display area for displaying media clips that are part of the composite media presentation. Specifically, the timeline in some embodiments displays one or more geometric shapes that represent one or more media clips that are part of the composite presentation. The timeline of some embodiments includes a primary lane (also called “spine”) as well as one or more secondary lanes (also called “anchor lanes”). The spine represents a primary sequence of media, which, in some embodiments, does not have any gaps. When a clip is deleted or removed from the timeline, the media-editing applications automatically closes the gap created in place of the clip. The clips in the anchor lanes are anchored to a particular position along the spine (or along a different anchor lane). Anchor lanes may be used for compositing (e.g., removing portions of one video and showing a different video in those portions), B-roll cuts (i.e., cutting away from the primary video to a different video whose clip is in the anchor lane), audio clips, or other composite presentation techniques. 
     The media editing application of some embodiments also includes a clip browser, which displays media clips that can be brought into the timeline to be part of the media presentation. The media editing application also includes a preview display area that displays frames of media clips in the clip browser or in the timeline. 
     The media-editing application of some embodiments allows the user to edit the media presentation by moving a media clip from one location to another location within a timeline or from an area out of the timeline into the timeline. For instance, the user can drag a media clip from a media browser into the spine or into an anchor lane to anchor the media clip to another media clip in the spine. The media-editing application displays during this drag operation the results of the operation. For instance, when a first media clip is dragged into the second media clips in the spine and collides with the second media clips, the media editing application moves the second media clips along the spine to make a room in the spine for the first media clip. When the first media clip is dragged into an anchored media clip that is in an anchor lane, the media editing application moves the anchored media clip into another anchor lane that may be above or below the anchor lane that the anchored media clip currently locates. The up or down movement of the anchored clips can be viewed as dynamic creation of anchor lanes. Some embodiments displays the movement of these media clips as they are being moved. 
     Some embodiments allow the user of the media-editing application to insert a media clip between two adjacent media clips within the timeline. The two adjacent media clips may be anchored clips or clips in the central compositing lane. Different embodiments provide different ways to insert a media clip between the two adjacent media clips. Some embodiments allow the user to drag a media clip from the clip browser or another media clip in the timeline into the border between the two media clips. The media-editing application of some embodiments allow to add a selected media clip from the clip browser between the two media clips as a playhead is passing close to the border between the two media clips. The two media clips move away from each other to create a space for the clip being inserted between the two clips. Some embodiments display the movement of the two clips as the two clips move to create the space. 
     Some embodiments shift the media clips (i.e., ripple the media clips in the timeline) away from a particular point along the timeline between the two media clips as a media clip is being inserted to the point. In other embodiments, the media-editing application does not ripple the media clips in the timeline when a media clip is dragged into the particular point in the timeline. These embodiments overwrite any clips or portions of clips with the clip being added for the duration of the clip being added starting at the particular point along the timeline. 
     Some embodiments allow a user of the media-editing application to append a first media clip to a second media clip in the timeline. The second media may be an anchored clip or a clip in the central compositing lane. Different embodiments provide different ways to append a media clip after another media clip. Some embodiments allow the user to drag a media clip from the clip browser or another media clip in the timeline to a right-edge of another media clip which does not have a media clip appended to the right edge. The media-editing application of some embodiments allow to append a selected media clip from the clip browser to the right edge of another media clip as a playhead is passing close to the right edge. Yet other embodiments allow the user to append a selected media clip from the clip browser after the last media clip in the central compositing lane by invoking a hot key command. 
     The media-editing application in some embodiments allows a user to delete a portion of the sequence of media clips in the timeline. In some embodiments, the user may select a full clip or multiple clips. Some embodiments allow the user to select a range that spans several clips. The media-editing application of some embodiments may also allow the user to select clips in the anchor lanes (rather than just the clips in the central compositing lane). Some embodiments move the media clips that were adjacent to the deleted media clip or range in order to close the gap created by the deleted media clip or range. Some embodiments displays the movement of the adjacent clips as they are moving to close the gap. 
     Some embodiments allow the user to anchor a media clip to another media clip in the timeline by selecting a single media clip or a range of media clip(s) from the clip browser and drag it above or below a media clip in the timeline. As described above, the media-editing application anchors a media clip only to a media clip in the central compositing lane. In other embodiments, the media clip to which another media clip is anchored may be any clip displayed in any lanes in the timeline. That is, the media-editing application of these embodiments allows the user to anchor a media clip to a media clip that is in the central compositing lane or to a media clip that is anchored to another media clip. 
     In some embodiments, the media-editing application allows the user to add an anchored clip into the central compositing lane. Some embodiments allow it by inserting an anchored clip between two adjacent clips or appending the anchored clip after the last media clip displayed in the central compositing lane. Also, some embodiments allow the user to replace a media clip or a selected range over one or more media clips in the central compositing lane with an anchored clip. 
     In some embodiments, an anchored media clip is represented as a rectangular shape. Each anchored media clip also has an anchor, which is represented as a pointer attached to the rectangular shape that connects the rectangular shape and a media clip displayed in the central compositing lane of a timeline. When a first media clip is anchored to a second media clip that is displayed in the central compositing lane, the anchor of the first media clip points to a position along the length of the second media clip. In some embodiments, the media-editing application displays a frame of the media clip represented by that position in the preview display area, when the first media clip is selected. 
     Some embodiments allow the user of the application to select two or more clips in different anchor lanes of the timeline to move together. This allows preserving the timing information between the selected anchored clips when the clips are placed in different positions along the timeline. Some embodiments allow the user to create duplicate copies of one or more media clips displayed in the timeline and place the duplicate copies of the clips in another location within the timeline. The media-editing application preserves relative timing information between two or more anchored media clips when the duplicate copies of them are placed in another location within the timeline. 
     In some embodiments, the media-editing application snaps a first media clip to a second media clip when the user drags (e.g., by a cursor operation) the first media clip close to the second media clip from either side of the second media clip. For instance, when the user moves the first media clip from the right side of the second media clip, the media-editing application snaps the left edge of the first media clip to the right edge of the second media clip. Conversely, when the user moves the first media clip from the left side of the second media clip, the media-editing application snaps the right edge of the first media clip to the left edge of the media clip. The media-editing application applies this snapping feature to any types of clips in any lanes (central compositing lanes, anchor lanes, etc.) that may be displayed in the timeline. 
     As will be described further below, some embodiments may move away the second clip to make room for the first media clip. Also, some embodiments may temporarily superimpose the second clip to prompt for replacement options. Therefore, the media-editing application of some embodiments uses a set of criteria to determine which moving operation to perform. The set of criteria may include the velocity of the first media clip at which the second media clip is moving to the, types of clips the first and second clips are, the direction in which the first media clip is approaching the second media clip, the origin (e.g., a clip browser, a timeline, etc.) from which the first media clip is moving, etc. 
     As described above, an anchored clip&#39;s media content is composited with (e.g., overlay, superimpose, mix, etc.) the media content of the media clip in a compositing lane. When there are multiple anchored clips at a position along the timeline, the media content of an anchored clip in an upper anchor lane takes the priority over the media content of a media clip in a lower lane in some embodiments. By allowing vertical swapping, the media-editing application provides a simple way of changing priorities of the anchored clips. 
     In addition to dynamically displaying different edits to the timeline, the media editing application in some embodiments can dynamically display the results of such edits in the preview display area. That is, the media editing application in these embodiments has a preview generator that can display previews of the media presentation on the fly as media clips are being dragged into and within the timeline. This allows the user of the media-editing application to see and hear the results of the operation while performing them. For instance, as a playhead moves along the timeline (i.e., as the media-editing application playbacks the media presentation), the media-editing application displays a composite frame of the media presentation represented by a point along the timeline at which the playhead is positioned currently. When any part of a media clip occupies a point along the timeline at the moment the playhead is passing the point, the media-editing application will factor that media clip into the composite image displayed for that point. 
     Some embodiments provide a media-editing application with novel editing tools. The media editing application provides an in-line precision editor. That is, the media-editing application opens the precision editor directly in the timeline. For instance, in some embodiments, the selection of an edge between two clips breaks the spine into two tracks, a top track and a bottom track. The top track is then used to perform edits to the left side of the selected edge, while the bottom track is used to perforin precision edits to the right side of the selected edge. In some embodiments, the top track shows the additional media content available for the clip that is on the left side of the edge to include. The bottom track shows the additional media content available for the clip on that is the right side of the edge to include. The additional media content is in the source media file, of which a clip represents a portion. In some embodiments, while the precision editor is opened, the media-editing application displays anchor lanes when any anchored clip exists and allows the user to edit any anchored clips in the displayed anchored lanes. 
     A media clip in some embodiments includes different types of media content. For instance, an audio and video clip has both video and audio content. In some such embodiments, a media clip includes different “tracks” for each type of media content. For instance, an audio content of an audio clip may include several tracks for several audio channels. Likewise, a video content of a video clip may include several tracks for, e.g., a foreground video and a background video. 
     The media-editing application of some embodiments provides another multi-tracked editing tool. This multi-track editing tool is also an in-line tool. That is, the media-editing application opens this multi-tracked editing tool within the timeline as a new “page” in some embodiments. In some embodiments, the media-editing application displays only the inside of a selected media clip of which to edit the tracks. No other media clips of the media presentation be displayed when the selected media clip is opened as a new page for multi-track editing. This multi-tracked editing tool opens different tracks contained in a media clip in different lanes to allow the user to edit individual tracks of the media clip independently. In some embodiments, the multi-tracked editing tool opens different tracks of a media clip in a central compositing lane and a set of anchor lanes. Each lane will include a track of a media clip in these embodiments. In some embodiments, the media-editing application does not display in the tool any other media clips that were displayed in the timeline before the tool was opened. 
     A transition effect is an effect used to impact the transition from one media clip of a media presentation to the next media clip. There are many types of transition effects. A common type of transition effect is a fade-out effect where the content of the outgoing media clip (i.e., the first clip of the two consecutive clips) gradually fades out as the content of the incoming media clip (i.e., the second clip of the two clips) gradually fades in. To apply a transition effect between two adjacent media clips, both media clips must have additional media content that overlap past the edit point in some embodiments. That is, the incoming media clip has to have media content before its in-point and the outgoing media clip has to have media content beyond its out-point. The media-editing application uses these additional media contents to show the transitional effect instead of an abrupt cut between the two media clips. In the case of a fade-out, the additional media content of the incoming media clip starts to fade in before the clip&#39;s in-point (i.e., before the outgoing clip&#39;s out-point). Likewise, the additional media content of the outgoing media clip keeps fading out beyond the clip&#39;s out-point (i.e., beyond the incoming clip&#39;s in-point). 
     The media-editing application of some embodiments displays in the timeline a transition as a rectangle between two media clips. In some embodiments, the media-editing application allows the user of the media-editing application to adjust the transition by manipulating the rectangle. For instance, the media-editing application allows the user to grab either side edges of the rectangle to adjust the points in time at which the incoming media clip starts to fade in or the outgoing media clip finishes fading out. The media-editing application may also allow the user to perform a rolling edit (i.e., adjusting the in-point of the incoming clip and the out-point of the outgoing media clip at the same time) by grabbing and dragging a middle portion of the rectangle. 
     When a transition is applied between two consecutive media clips of the media presentation, the media-editing application in some embodiments covers portions of the two media clips with the rectangle such that the covered portions are not visible in the timeline. In some such embodiments, the media-editing application displays the rectangle transparently such that each of the two media clips to which the transition effect is applied is visible. That is, the portions of the two media clips that are overlaid with the transition tool are visible because the transition tool is transparent. 
     As described above, a media clip in some embodiments contains one or more types of media content (e.g., audio, video, text, image, etc.). When a transition is applied between two adjacent media clips in the timeline of some embodiments, the media-editing application allows the user to adjust the transition such that the adjustment affects all types of media content that the two media clips have. For instance, the media-editing application allows the user to drag the right side edge of a transition to adjust the point in time at which both the audio and video content of the outgoing media clip finish fading out. In some such embodiments, the media-editing application also allows the user to adjust different types of media contents separately. For instance, the media-editing application allows the user to adjust the audio contents of the two media clips without affecting the video contents of the two clips by manipulating only the audio portions of the two media clips in the timeline. Also, the media-editing application allows the user to adjust the video transition independently from the audio transition. For instance, the media-editing application allows for moving the video portion of the transition along the timeline independently from the audio portion of the transition. Furthermore, the media-editing application allows the user to adjust one or more types of media contents at the same time and without affecting other contents of the media clips. 
     When a media clip in the timeline of some embodiments is trimmed from its beginning (i.e., when the media clip&#39;s in-point is pulled in), the media-editing application moves the media clips that come after the media clip being trimmed to the left while leaving the media clips that come before the media clip being trimmed static. This results in an impression to the user that the media clip that is being trimmed is trimmed from its ending. That is, this gives an impression that the out-point of the media clip (i.e., the right edge of the clip) that is being trimmed is pulled in (to the left). To avoid causing such impression, some embodiments of the media application moves to the right the media clips that come before the media clip being trimmed from its beginning. That is, when a media clip is trimmed on the beginning side of the media clip, media clips that come before the media clip being trimmed moves in the direction of trimming. 
     The preceding Summary is intended to serve as a brief introduction to some embodiments of the invention. It is not meant to be an introduction or overview of all inventive subject matter disclosed in this document. The Detailed Description that follows and the Drawings that are referred to in the Detailed Description will further describe the embodiments described in the Summary as well as other embodiments. Accordingly, to understand all the embodiments described by this document, a full review of the Summary, Detailed Description and the Drawings is needed. Moreover, the claimed subject matters are not to be limited by the illustrative details in the Summary, Detailed Description and the Drawing, but rather are to be defined by the appended claims, because the claimed subject matters can be embodied in other specific forms without departing from the spirit of the subject matters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the invention are set forth in the appended claims. However, for purposes of explanation, several embodiments of the invention are set forth in the following figures. 
         FIG.  1    illustrates a graphical user interface (GUI) of a media-editing application of some embodiments. 
         FIG.  2    illustrates an example of modifying the audio content of a media clip that includes both audio and video contents in a timeline of a media-editing application. 
         FIG.  3    illustrates a timeline of a media-editing application having two playheads. 
         FIG.  4    illustrates an example of inserting a media clip between two adjacent media clips in a timeline of a media-editing application. 
         FIG.  5    illustrates an example of appending a media clip to another media clip displayed in the timeline. 
         FIG.  6    illustrates an example of deleting a selected range of a media clip displayed in a timeline of a media-editing application. 
         FIG.  7    illustrates an example of anchoring a media clip to another media clip displayed in a timeline of a media-editing application. 
         FIG.  8    illustrates an example of anchoring a media clip to another media clip displayed in a timeline of a media-editing application. 
         FIG.  9    illustrates an example of anchoring a media clip to another media clip displayed in a timeline of a media-editing application. 
         FIG.  10    illustrates an example of moving an anchored media clip into a central compositing lane in a timeline of a media-editing application. 
         FIG.  11    illustrates an example of moving an anchored clip along an anchor lane in a timeline of a media-editing application. 
         FIG.  12    illustrates an example of moving multiple anchored clips along an anchor lane in a timeline of a media-editing application. 
         FIG.  13    illustrates an example of duplicating anchored clips in anchor lanes of a timeline of a media-editing application. 
         FIG.  14    illustrates an example of horizontal snapping of two media clips displayed in a timeline of a media-editing application. 
         FIG.  15    illustrates an example of vertical swapping of two anchored media clips in two different anchor lanes in a timeline of a media-editing application. 
         FIG.  16    illustrates a timeline of a media-editing application that displays results of editing operations as the editing operations are being performed. 
         FIG.  17    conceptually illustrates a process of some embodiments for rearranging positions of media clips in a timeline while a media clip is being dragged over or extended into different regions of the timeline. 
         FIG.  18    conceptually illustrates a process of some embodiments for placing media clips in a timeline when a media clip has moved to a new position in the timeline. 
         FIG.  19    illustrates an example of placing media clips in a timeline. 
         FIG.  20    conceptually illustrates a GUI of a media-editing application that displays results of editing operations in the preview display area as the editing operations are being performed. 
         FIG.  21    conceptually illustrates a process for incorporating edits into playback of a video sequence in real-time. 
         FIG.  22    conceptually illustrates an in-line multi-tracked editing tool for a timeline of a media-editing application. 
         FIG.  23    conceptually illustrates an example of an in-line precision editing tool for a timeline of a media-editing application. 
         FIG.  24    illustrates an example of the movement of an anchored clip in the middle of a transition modification operation. 
         FIG.  25    illustrates an example of adjusting a transition between two media clips in a timeline of a media-editing application. 
         FIG.  26    illustrates an example of adjusting a transition between two media clips in a timeline of a media-editing application. 
         FIG.  27    illustrates expanding a space before the first media clip of a media presentation that is displayed in a timeline of a media-editing application. 
         FIG.  28    conceptually illustrates a process of some embodiments for creating an asset data structure and a clip data structure referencing that asset. 
         FIG.  29    conceptually illustrates an asset data structure for a video asset, as well as an event data structure for an event that contains the video asset. 
         FIG.  30    conceptually illustrates a process of some embodiments for generating an asset ID and storing the ID in the data structure. 
         FIG.  31    conceptually illustrates a clip data structure that contains a single asset. 
         FIG.  32    conceptually illustrates a nested sequence of clip objects created by the media-editing application of some embodiments for an imported media file. 
         FIG.  33    conceptually illustrates objects nested in a conceptual timeline. 
         FIG.  34    illustrates a timeline of some embodiments. 
         FIG.  35    conceptually illustrates a subset of the data structures for the sequence illustrated in  FIG.  34   . 
         FIG.  36    conceptually illustrates objects nested in a conceptual timeline. 
         FIG.  37    conceptually illustrates a state diagram for a media-editing application of some embodiments. 
         FIG.  38    conceptually illustrates a software architecture of a media-editing application of some embodiments. 
         FIG.  39    conceptually illustrates an electronic system with which some embodiments of the invention are implemented. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the invention, numerous details, examples, and embodiments of the invention are set forth and described. However, it will be clear and apparent to one skilled in the art that the invention is not limited to the embodiments set forth and that the invention may be practiced without some of the specific details and examples discussed. 
     For a media-editing application that creates a composite media presentation, some embodiments of the invention provide a novel compositing display area in which several media clips can be arranged for compositing. This novel compositing display area will be referred to as a “timeline” throughout this application unless specified otherwise. This timeline of some embodiments is capable of performing numerous novel features, some of which will be described in detail further below. 
     A media clip in some embodiments is a piece of media content. Examples of types of media content include audio data, video data, audio and video data, text data, image/picture data, and/or other media data. In some embodiments, a media clip can be a video clip or an audio clip. In other embodiments, a media clip can be a video clip, an audio clip, an audio and video clip, a sequence of media clips (also referred to as a media clip sequence), a text clip, a text overlay, a still image or picture, or any other type of media clip that can be used to create a composite presentation. In this application, a media clip may also refer to the graphical representation of the media clip in the GUI of a media-editing application of some embodiments. 
     A media clip that has a temporal component (e.g., audio media clips, video media clips, audio and video media clips, etc.) is further defined by an in-point and an out-point with respect to a source media file in some embodiments. In some such embodiments, the source media file is stored on the computing device on which the media-editing application executes or on a computing device to which the media-editing application has access. A media clip&#39;s in- and out-points define its start and end points with respect to the source media file. 
     The in- and out-points of a media clip can be defined as such to cover an entire source media file or a portion of the source media file in some embodiments. Several media clips can define different in- and out-points with respect to the same source media file such that each media clip has a different media content. For instance, the in- and out-points of a media clip can be defined to be the first half of a source media file while the in and out points of another media clip can be defined to be the second half of the same source media file. 
     In some embodiments, a media clip can serve as another media clip&#39;s source. For instance, the media-editing application allows the user to select a range (i.e., a length along the length of a graphical representation of a media clip that corresponds to a duration within the media clip) and use the selected range like a media clip. 
     Several detailed embodiments of the invention are described in the sections below. Section I describes various features of the spine-based timeline in some embodiments. Section II describes various edit operations that the media-editing application performs on the media clips displayed in the spine based timeline. Section III describes displaying a preview of a media presentation as the presentation is being edited. Section IV then describes several editing tools that the media-editing application provides. Next, section V describes data structures of media clips used by some embodiments. Section VI describes the software architecture of a media-editing application of some embodiments. Finally, Section Vii describes an electronic system that implements some embodiments of the invention. 
     I. Timeline 
     A. Introduction 
       FIG.  1    illustrates a graphical user interface (GUI)  100  of a media-editing application of some embodiments. One of ordinary skill will recognize that the graphical user interface  100  is only one of many possible GUIs for such a media-editing application. In fact, the GUI  100  includes several display areas which may be adjusted in size, opened or closed, replaced with other display areas, etc. The GUI  100  includes a clip library  105 , a clip browser  110 , a timeline  115 , a preview display area  120 , an inspector display area  125 , an additional media display area  130 , and a toolbar  135 . 
     The clip library  105  includes a set of folders through which a user accesses media clips that have been imported into the media-editing application. Some embodiments organize the media clips according to the device (e.g., physical storage device such as an internal or external hard drive, virtual storage device such as a hard drive partition, etc.) on which the media represented by the clips are stored. Some embodiments also enable the user to organize the media clips based on the date the media represented by the clips was created (e.g., recorded by a camera). As shown, the clip library  105  includes media clips from both 2009 and 2011. 
     Within a storage device and/or date, users may group the media clips into “events”, or organized folders of media clips. For instance, a user might give the events descriptive names that indicate what media is stored in the event (e.g., the “New Event 2-8-09” event shown in clip library  105  might be renamed “European Vacation” as a descriptor of the content). In some embodiments, the media files corresponding to these clips are stored in a file storage structure that mirrors the folders shown in the clip library. 
     Within the clip library, some embodiments enable a user to perform various clip management actions. These clip management actions may include moving clips between events, creating new events, merging two events together, duplicating events (which, in some embodiments, creates a duplicate copy of the media to which the clips in the event correspond), deleting events, etc. In addition, some embodiments allow a user to create sub-folders of an event. These sub-folders may include media clips filtered based on tags (e.g., keyword tags). For instance, in the “New Event 2-8-09” event, all media clips showing children might be tagged by the user with a “kids” keyword, and then these particular media clips could be displayed in a sub-folder of the event that filters clips in this event to only display media clips tagged with the “kids” keyword. 
     The clip browser  110  allows the user to view clips from a selected folder (e.g., an event, a sub-folder, etc.) of the clip library  105 . As shown in this example, the folder “New Event 2-8-11 3” is selected in the clip library  105 , and the clips belonging to that folder are displayed in the clip browser  110 . Some embodiments display the clips as thumbnail filmstrips, as shown in this example. By moving a cursor (or a finger on a touchscreen) over one of the thumbnails (e.g., with a mouse, a touchpad, a touchscreen, etc.), the user can skim through the clip. That is, when the user places the cursor at a particular horizontal location within the thumbnail filmstrip, the media-editing application associates that horizontal location with a time in the associated media file, and displays the image from the media file for that time. In addition, the user can command the application to play back the media file in the thumbnail filmstrip. 
     In addition, the thumbnails for the clips in the browser display an audio waveform underneath the clip that represents the audio of the media file. In some embodiments, as a user skims through or plays back the thumbnail filmstrip, the audio plays as well. There are several types of clips. An audio and video clip is a clip that contains both audio and video content. An audio clip is a clip that contains only audio content. A video clip is a clip that contains only video content. 
     Many of the features of the clip browser are user-modifiable. For instance, in some embodiments, the user can modify one or more of the thumbnail size, the percentage of the thumbnail occupied by the audio waveform, whether audio plays back when the user skims through the media files, etc. In addition, some embodiments enable the user to view the clips in the clip browser in a list view. In this view, the clips are presented as a list (e.g., with clip name, duration, etc.). Some embodiments also display a selected clip from the list in a filmstrip view at the top of the browser so that the user can skim through or playback the selected clip. 
     The timeline  115  provides a visual representation of a composite presentation (or project) being created by the user of the media-editing application. Specifically, it displays one or more geometric shapes that represent one or more media clips that are part of the composite presentation. The timeline  115  of some embodiments includes a primary lane (also called a “spine”, “primary compositing lane”, or “central compositing lane”) well as one or more secondary lanes (also called “anchor lanes”) above and/or below the primary lane. The spine represents a primary sequence of media which, in some embodiments, does not have any gaps. The clips in the anchor lanes are anchored to a particular position along the spine (or along a different anchor lane). Anchor lanes may be used for compositing (e.g., removing portions of one video and showing a different video in those portions), B-roll cuts (i.e., cutting away from the primary video to a different video whose clip is in the anchor lane), audio clips, or other composite presentation techniques. 
     Clips placed in the anchor lanes are referred to as “anchored clips.” As an example,  FIG.  1    shows a media clip  175  that is anchored off of another media clip  180  in the timeline  115 . In some of these embodiments, media clips can be placed in these anchor lanes to anchor off of media clips in the central compositing lane  150 . Instead of, or in conjunction with, having several levels of media clips that anchor off the central compositing lane  150 , some embodiments allow media clips to be placed in these anchor lanes and to be anchored off of other anchored media clips placed in these anchor lanes. To help the user distinguish the central compositing lane  150  and the anchored lanes in the timeline  115 , some embodiments use different tones for these lanes. For instance, the timeline  115  uses a darker tone for the central compositing lane  150  than the tone for the anchored lanes  155 ,  160 , and  165 . 
     As shown, the timeline  115  can place different types of media clips in the same lane (a central compositing lane or an anchored lane). Also, the timeline  115  can place different types of media clips in the anchor lanes above and below the central compositing lane. In other words, the timeline  115  can place a media clip of any type (e.g., audio clip, video clip, audio and video clip, etc.) in any lane of the timeline  115 . 
     Also, when there are multiple anchored clips at a position along the timeline  115 , the media content of an anchored clip in an upper anchor lane takes the priority over the media content of a media clip in a lower lane in some embodiments. For instance, the video content of the media clip in the uppermost anchor lane will be the content of the presentation for the period time along the timeline that the media clip spans. 
     As with the clips in the clip browser, the user can skim through the timeline or play back the timeline (either a portion of the timeline or the entire timeline). In some embodiments, the playback (or skimming) is not shown in the timeline clips, but rather in the preview display area  120 . 
     The preview display area  120  (also referred to as a “viewer”) displays images from media files that the user is skimming through, playing back, or editing. These images may be from a composite presentation in the timeline  115  or from a media clip in the clip browser  110 . In this example, the user has been skimming through the beginning of clip  140 , and therefore an image from the start of this media file is displayed in the preview display area  120 . As shown, some embodiments will display the images as large as possible within the display area while maintaining the aspect ratio of the image. 
     The inspector display area  125  displays detailed properties about a selected item and allows a user to modify some or all of these properties. The selected item might be a clip, a composite presentation, an effect, etc. In this case, the clip that is shown in the preview display area  120  is also selected, and thus the inspector displays information about media clip  140 . This information includes duration, file format, file location, frame rate, date created, audio information etc. about the selected media clip. In some embodiments, different information is displayed depending on the type of item selected. 
     The additional media display area  130  displays various types of additional media, such as video effects, transitions, still images, titles, audio effects, standard audio clips, etc. In some embodiments, the set of effects is represented by a set of selectable UI items, each selectable item representing a particular effect. In some embodiments, each selectable UI item also includes a thumbnail age with the particular effect applied. The display area  130  is currently displaying a set of effects for the user to apply to a clip. In this example, only two effects are shown in the display area (the keyer effect and the luma keyer effect, because the user has typed the word “keyer” into a search box for the effects display area). 
     The toolbar  135  includes various selectable items for editing, modifying what is displayed in one or more display areas, etc. The right side of the toolbar includes various selectable items for modifying what type of media is displayed in the additional media display area  130 . The illustrated toolbar  135  includes items for video effects, visual transitions between media clips, photos, titles, generators and backgrounds, etc. In addition, the toolbar  135  includes an inspector selectable item that causes the display of the inspector display area  125  as well as items for applying a reaming operation to a portion of the timeline, adjusting color, trimming, anchoring, creating position clips, and other functions. 
     The left side of the toolbar  135  includes selectable items for media management and editing. Selectable items are provided for adding clips from the clip browser  110  to the timeline  115 . In some embodiments, different selectable items may be used to add a clip to the end of the spine, add a clip at a selected point in the spine (e.g., at the location of a playhead), add an anchored clip at the selected point, perform various trim operations on the media clips in the timeline, etc. The media management tools of some embodiments allow a user to mark selected clips as favorites, among other options. 
     One or ordinary skill will also recognize that the set of display areas shown in the GUI  100  is one of many possible configurations for the GUI of some embodiments. For instance, in some embodiments, the presence or absence of many of the display areas can be toggled through the GUI (e.g., the inspector display area  125 , additional media display area  130 , and clip library  105 ). In addition, some embodiments allow the user to modify the size of the various display areas within the UI. For instance, when the display area  130  is removed, the timeline  115  can increase in size to include that area. Similarly, the preview display area  120  increases in size when the inspector display area  125  is removed. 
     B. Volume Control 
       FIG.  2    illustrates an example of modifying the audio content of a media clip that includes both audio and video contents in a timeline of a media-editing application. Specifically, this figure illustrates a timeline  200  in eight different stages  205 - 240  to show changing volume level of the audio of a media clip  250  displayed in the timeline  200 .  FIG.  2    illustrates a media clip  245  and the media clip  250  displayed in the timeline  200 . The timeline  200  is similar to the timeline  115  described, above by reference to  FIG.  1   . 
     The media-editing application of some embodiments provides a volume control for a user of the application to control the volume of a media clip displayed in the timeline  200 . The audio portion of a media clip displayed in the timeline  200  includes a volume control. The volume control in some embodiments appears as a horizontal line across the waveform in the audio portion as shown in the stage  215  of this figure. As the user drags the line upwards or downwards, the media-editing application changes the volume of the audio content of the media clip. 
     The media-editing application also allows the user to select a range of media clips displayed in the timeline  200  such that the user can selectively control the volume of the selected range. The audio portion in some embodiments includes fade handles  221  and  222 , which appear near both ends of the waveform in the selected range as shown in the stage  225  of this figure. The user can control fading of the audio content by dragging the handles along the volume control line. 
     In some embodiments, the media-editing application provides a set of volume patterns for the user to select. By choosing a pattern and dragging volume control knobs  254  and  255  (shown in the stages  235  and  240 ), the user can apply the selected volume pattern to the audio content of the media clip. The volume control knob also moves along the volume level control line. Using the volume control knob  254 , the user can apply a selected pattern from the beginning of a clip. The volume control knob  255  allows the user to apply a selected pattern from the end of a clip. 
     In the first stage  205 , the timeline  200  displays a media clip  250 , which includes both audio and media contents. Accordingly, the media clip  250  includes an audio portion  252  and a video portion  251  in its representation in the timeline  200 . In the second stage  210 , the timeline  200  highlights a volume control line  253  when the user selects the line  253  by a click operation. 
     In the third stage  215  the user drags the volume control line  253  upwards in order to increase the volume of the audio content of the media clip  250 . In the fourth stage  220 , the user selects (e.g., by a click operation) a range of the media clip  250 . In the fifth stage  225 , the user brings down a portion of the volume control line  253  that falls within the selected portion. As a result, the volume is leveled down for the duration of the media clip represented by the selected portion. 
     In the sixth stage  230 , the timeline  200  displays a menu  231  for volume patterns when the user selects a volume control knob (behind the menu  231 ) by a click operation. The user can then select a volume pattern from the menu  231 . In this example, the user selects “Linear.” in the seventh stage  235 , the timeline  200  applies the selected volume pattern as the user drags the control knob  254  to the right. In the eighth stage  240 , the timeline  200  shows the selected pattern more apparently as the user drags the control knob  254  to the right end of the media clip  250 . 
     C. Multiple Playheads 
       FIG.  3    illustrates a timeline of a media-editing application having two playheads. Specifically, this figure illustrates a GUI  300  in two different stages  305  and  310  to show that a timeline  315  includes two playheads for editing and playing back a media presentation. The GUI  300  includes the timeline  315  and a viewer  320 . The timeline  315  and the viewer  320  are similar to the timeline  115  and the viewer  120  described above by reference to  FIG.  1   . 
     The timeline  315  of some embodiments provides two playheads, a skimming playhead  330  and a primary playhead  325 . A playhead in some embodiments appears as a vertical line in the timeline  315 . A video frame of the media presentation that the playhead is positioned at is displayed in the viewer  320 . A portion of audio content that corresponds to the frame will also be output to an audio output device by the media-editing application. The skimming playhead  330  is a playhead that matches the position of the cursor in the timeline  315 . The primary playhead  325  is a static playhead that scrolls across the timeline  315  during playback or can be selected and moved across the timeline by the user of the media-editing application. The primary playhead specifies a current editing position in the timeline  315 , while the skimming playhead specifies a skimming position in the timeline  315 . 
     When the cursor (not shown) enters the timeline  315 , the skimming playhead appears and becomes the editing position, since it is the point of focus. It will override the primary playhead  325  when it is present in the timeline  315 . When the cursor leaves the timeline and enters another portion of the GUI  300 , the primary playhead  325  is the current editing position. The primary playhead  325  allows the user to leave the timeline without losing the video frame of interest. As will be described further below, the primary playhead  325  also allows the user to use hotkey edits to add, remove or modify the content of the media presentation at the position of the primary playhead. Also, when the media presentation is previewed (i.e., when the media presentation is played back instead of being skimmed), the two playheads synch up and move together horizontally along the timeline  315  in some embodiments. Also, in some embodiments, different colors are used to represent the different playheads. For instance, a red color is used for the skimming playhead  330  and a gray color is used for the primary playhead  325  in some such embodiments. 
     In the first stage  305 , the primary playhead  325  is placed at a position of the timeline  315  so that the playhead intersects with the media clip  335 . In some embodiments, each point along the length of a media clip represents a video frame of the media clip. As shown, the media-editing application displays in the viewer  320  a frame of the media clip  335  represented by a point along the timeline  315  at which the primary playhead  325  is positioned currently. 
     In the second stage  310 , the skimming playhead  330  appears as a cursor  331  enters into the timeline  315 . The skimming playhead  330  is placed at a position of the timeline  315  such that the playhead intersects with the media clip  340 . As shown, the media-editing application displays in the viewer  320  a frame of the media clip  340  represented by a point along the timeline  315  at which the skimming playhead  330  is positioned currently in some embodiments. When the cursor leaves the timeline  315 , the skimming playhead  330  will disappear from the timeline  315  and the viewer  320  will display the video frame that it displayed in the first stage  305  because the primary playhead  325  has not been moved to another position in the timeline  315 . 
     II. Live Drag 
     A. Inserting a Media Clip 
       FIG.  4    illustrates an example of inserting a media clip between two adjacent media clips in a timeline  401  of a media-editing application. Specifically, this figure illustrates a GUI  400  in four different stages  405 - 420  that the media-editing application allows the user to add a media clip  425  to the timeline  401  by inserting it between two media clips  430  and  435  displayed the timeline  401 . The GUI  400  is similar to the GUI  100  described above by reference to  FIG.  1    in that the GUI  400  includes a clip browser  445  and the timeline  401  which are similar to the clip browser  110  and the timeline  115 , respectively. The timeline  401  includes a central compositing lane  440 . 
     Some embodiments allow a user of the media-editing application to insert a media clip between two adjacent media clips within the timeline  401 . The two adjacent media clips may be anchored clips or clips in the central compositing lane  440 . Different embodiments provide different ways to insert a media clip between the two adjacent media clips. Some embodiments allow the user to drag a media clip from the clip browser  445  or another media clip in the timeline  401  into the border between the two media clips. The media-editing application of some embodiments allow to add a selected media clip from the clip browser  445  between the two media clips as a playhead is passing close to the border between the two media clips. 
     Some embodiments shift the media clips (i.e., ripple the media clips in the timeline) away from a particular point along the timeline  401  between the two media clips as a media clip is being inserted to the point. In other embodiments, the media-editing application does not ripple the media clips in the timeline when a media clip is dragged into the particular point in the timeline. These embodiments overwrite any clips or portions of clips with the clip being added for the duration of the clip being added starting at the particular point along the timeline. 
     As shown, the created space for the media clip  425  is indicated by the highlighted boundary  490  in this example. In some embodiments, the media-editing application performs this movement in an animated motion, thereby creating an animated effect of the sliding of the clips in the timeline away from the point of insertion to make room for the inserted clip(s). 
     In the first stage  405 , the timeline  401  displays media clips  430  and  435  in the central compositing lane  440 . In the second stage  410 , the user selects (e.g., by a click operation, etc.) a media clip  425  displayed in the clip browser  445  to bring into the timeline  401 . In the third stage  415 , the user drag the selected media clip and hovers over the two media clips  430  and  435  in between of which the user wants to insert the media clip  425 . The media clip  435  moves away from the particular point  485  in between the two media clips  430  and  445  to make room for the media clip  425 . 
     The fourth stage  420  illustrates the completion of the insertion of the media clip  425  into the particular point  485  of the timeline  401 . In some embodiments, the media-editing application snaps the media clip  425  into the space  490  that was created for the media clip  480  in the third stage  415 . 
     B. Appending a Media Clip 
       FIG.  5    illustrates an example of appending a media clip to another media clip displayed in the timeline  401 . Specifically, this figure illustrates the GUI  400  in three different stages  505 - 515  to show that the media-editing application allows the user of the application to append a media clip  520  to the end of the sequence of media clips  525  and  535  in the timeline  401 . 
     Some embodiments allow a user of the media-editing application to append a first media clip to a second media clip in the timeline  401 . The second media may be an anchored clip or a clip in the central compositing lane  440 . Different embodiments provide different ways to append a media clip after another media clip. Some embodiments allow the user to drag a media clip from the clip browser  445  or another media clip in the timeline  401  to a right-edge of another media clip which does not have a media clip appended to the right edge. The media-editing application of some embodiments allow to append a selected media clip from the clip browser  445  to the right edge of another media clip as a playhead is passing close to the right edge. Yet other embodiments allow the user to append a selected media clip from the clip browser  445  after the last media clip in the central compositing lane  440  by invoking a hot key command. 
     In the first stage  505 , the timeline  401  displays media clips  525  and  535  in the central compositing lane  440 . As shown, the media clip  535  is the last media clip of the sequence of the two media clips. In the second stage  510 , the user selects a range of a media clip  520  (e.g., selected via a cursor controller operation, selected from a keystroke, etc.) from the clip browser  545  towards the right edge of the media clip  535 . The third stage  515  illustrates the completion of appending the media clip  520  to the media clip  535 . The selected range of the media clip  520  appears at the end of the sequence in the timeline  401 . In some embodiments, the media-editing application snaps the media clip  520  to the right edge of the media clip  535 . 
     C. Deleting a Media Clip 
       FIG.  6    illustrates an example of deleting a selected range of a media clip displayed in a timeline  600  of a media-editing application. Specifically, this figure illustrates the timeline  600  in three different stages  605 - 615  to show the deletion of a range of a media clip that is less than the whole media clip displayed in the timeline  600 . As shown, the central compositing lane  645  displays a composite presentation of media clips that includes media clips  625 - 635 . 
     The media-editing application in some embodiments allows a user to delete a portion of the sequence of media clips in the timeline  600 . In some embodiments, the user may select a full clip or multiple clips. Some embodiments allow the user to select a range that spans several clips. The media-editing application of some embodiments may also allow the user to select clips in the anchor lanes (rather than just the clips in the central compositing lane). 
     The first stage  605  shows the timeline  600  including clips  625 - 635  before the user performs a deletion operation. The second stage  610  illustrates a selection of a particular portion  640  of the timeline  600  (e.g., through a cursor controller operation, through a keyboard selection of the starting and ending point, through defining a starting point and a range). In this example, the selected particular portion  640  is a portion of the media clip  630  (e.g., two and a half frames within media clip  630 ). 
     The third stage  615  illustrates the deletion of the selected particular portion  640  from the timeline  600 . The user of the media-editing application may invoke a command to delete the selected portion  640  by performing keyboard operations (e.g., delete key), by selecting from a drop-down menu, by performing a cursor controller operation, etc. Upon the deletion of the selected portion  640 , the media-editing application deletes the selected portion  640 . As a result, the central compositing lane  645  no longer displays the selected portion  640 . The media clip  635 , which comes after the deleted portion, ripples (i.e., moves to the left on the central compositing lane  645 ) in order not to leave a gap in the central compositing lane  645 . 
     As illustrated by this example, the removal of the selected portion  640  shortens the total duration of the timeline  600  by the duration of the delete portion  640 . The media-editing application in some embodiments maintains the total duration of the timeline by replacing the selected portion with placeholder gaps in order to prevent ripple edits. While this example illustrates the removal of a media clip within the central compositing lane, the media-editing application may also allow the user to delete an anchored clip. 
     D. Anchoring a Media Clip 
       FIG.  7    illustrates an example of anchoring a media clip to another media clip displayed in a timeline of a media-editing application. Specifically, this figure illustrates a GUI  700  in two different stages  705  and  710  to show the media-editing application allows a user of the application to select a media clip from a clip browser and anchor the clip to another clip in the timeline  725 . The GUI  700  is similar to the GUI  100  described above by reference to  FIG.  1    in that the GUI  700  includes a clip browser  715 , a preview display area  720 , and a timeline  725  which are similar to the clip browser  110 , the preview display area  120 , and the timeline  115 , respectively. 
     Some embodiments allow the user to anchor a media clip to another media clip in the timeline  725  by selecting a single media clip or a range of media clip from the clip browser and drag it above or below a media clip in the timeline  725 . As described above, the media-editing application anchors a media clip only to a media clip in the central compositing lane  730 . In other embodiments, the media clip that is anchored to may be any clip displayed in any lanes in the timeline  725 . That is, the media-editing application of these embodiments allows the user to anchor a media clip to a media clip that is in the central compositing lane  730  or to a media clip that is anchored to another media clip. 
     In the first stage  705 , a media clip  750  has been selected from the clip browser  715 . The selection is received through a user selection input  755  such as input received from a cursor controller (e.g., a mouse, touchpad, trackpad, etc.), from a touchscreen (e.g., a user touching a UI item on a touchscreen), etc. 
     In the second stage  710 , a user has dragged the media clip  750  from the clip browser  715  and dropped it (by releasing the mouse button, “tap” of a touchscreen, etc.) in the anchor lane  740  above the central compositing lane  730  and before the anchored media clip  760  in the timeline  725 . The media-editing application anchors the media clip  750  to the media clip  765 . 
       FIG.  8    illustrates another example of anchoring a media clip to another media clip displayed in a timeline of a media-editing application. Specifically, this figure illustrates a GUI  800  in three different stages  810 ,  815 , and  820  to show that the media-editing application allows a user of the application to select a range of a media clip from a clip browser and anchor the selected range to several media clips as a primary playhead passes by those several media clips. The GUI  800  is similar to the GUI  100  described above by reference to  FIG.  1    in that the GUI  800  includes a clip browser  825 , and a timeline  830  which are similar to the clip browser  110  and the timeline  115 , respectively. The timeline  830  includes a playhead  845 , which is similar to the primary playhead  325  described above by reference to  FIG.  3   . 
     In some embodiments, the media-editing application allows the user of the application to anchor a first media clip to a second media clip in the timeline  830  based on the position of the playhead  845  along the timeline  830 . In some such embodiments, the media-editing application anchors the first media clip to the second media clip when the user invokes a command to anchor as the playhead  845  passes by a position along the length of the second media clip. In some embodiments, the second media clip must be a media clip in the central compositing lane  835 . In other embodiments, the second media clip can be any media clip placed in any lane of the timeline  830 . The media-editing application in these embodiments anchors a first media clip to a second media clip that does not have above it another anchored clip that intersects the playhead  845  at the moment the command to anchor is invoked. That is, these embodiments anchors the first media clip to the second media clip that is in the uppermost lane of the timeline  830  among the media clips that the playhead is intersecting at the moment. 
     In the first stage  805 , the timeline  830  displays media clips  831 - 833 . The second stage  805  illustrates a selection of a range in a media clip  850  from the clip browser  825  (e.g., by clicking a mouse button, tapping a touchpad, or touching a touchscreen). The media-editing application indicates the selection by a bolding of the border of that particular portion of the media clip  850 . In this example, the user selects a range of the media clip  850  to anchor to a media clip displayed in the timeline  830 . 
     In the third stage  815 , the user invokes a command provided by the media-editing application to anchor the selected range to a media clip displayed in the central composing lane  835 . At the moment when the command was invoked, the playhead  845  is placed at a position along the timeline that intersects with the media clip  831 . As a result, the media-editing application places the media clip  855  (the selected range of the media clip  850 ) to that position along the timeline and anchors the media clip  855  to the media clip  831  at that position. The in-point of the anchored media clip  855  coincides with the location of the playhead  845 . In some embodiments, the media-editing application places an anchor  860  at the in-point of the anchored clip  855 . The media-editing application places the anchor  860  that connects the anchored clip and the clip that is anchored at the in-point of the anchored clip  855 . 
     In the fourth stage  820 , the playhead  845  has continued to move along the timeline to the right as the media-editing application plays back the media clips in the central compositing lane  835 . The user invokes the command to anchor again when the playhead is intersecting the media clip  832 . The media-editing application anchors the selected range of the media clip  850  as a media clip to the media clip  832  at the position of the playhead  840 . In this manner, the media-editing application created duplicate copies of the selected range of the media clip  850  and anchored the copies to different media clips in the central compositing lane  835 . 
       FIG.  9    illustrates yet another example of anchoring a media clip to another media clip displayed in a timeline of a media-editing application. Specifically, this figure illustrates a timeline  900  in three different stages  905 - 915  to show that the media-editing application allows a user of the application to remove a media clip from a central compositing lane  920  and anchor it to another media clip in the central composing lane  920 . The timeline  900  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     The media-editing application of some embodiments allows the user to remove a media clip from the central compositing lane  920  and anchor it to another media clip in the timeline  900 . In some embodiments, the media-editing application allows the user to drag a first media clip out of the central compositing lane  920  and drop it above or below a second media clip to anchor the first media clip to the second media clip. The second media clip may be any media clip in any lane of the timeline  900 . 
     In the first stage  905 , the timeline  900  displays media clips  930 - 945  in the central compositing lane  920 . In the second stage  920 , the user selects the media clip  935  (e.g, by a click operation) and starts to drag it out of the central compositing lane  920 . 
     In the third stage  915 , the user drops the media clip  935  at a location above the media clip  930  in the timeline  900 . The media-editing application anchors the media clip  935  to the media clip  930  in the anchor lane  925  such that the anchor  950  points to a particular point along the length of the media clip  930 . 
     E. Moving an Anchored Clip into Central Compositing Lane 
       FIG.  10    illustrates an example of moving an anchored media clip into a central compositing lane in a timeline of a media-editing application. Specifically, this figure illustrates a timeline  1000  in four different stages  1005 ,  1010 ,  1015 , and  1020  to show that the media-editing application allows a user of the application to move an anchored clip  1025  from an anchor lane  1030  and place it between clips  1035  and  1040  that are displayed in a central compositing lane  1045 . The timeline  1000  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     In some embodiments, the media-editing application allows the user to add an anchored clip into the central compositing lane. Some embodiments allow it by inserting an anchored clip between two adjacent clips or appending the anchored clip after the last media clip displayed in the central compositing lane. Also, some embodiments allow the user to replace a media clip or a selected range over one or more media clips in the central compositing lane with an anchored clip. 
     At stage  1005 , the user selects the anchored clip  1025  has been selected from the anchor lane  1030  (e.g., by clicking a mouse button, tapping a touchpad, or touching a touchscreen). At stage  1010 , the user has dragged the anchored media clip  1025  from its previous location and hovers the media clip (without dropping it) over media clips  1035  and  1040  displayed on central compositing lane  1045  such that the left border line (in-point) of the media clip  1025  has covered a portion of the media clip  1040 . 
     At stage  1015 , the user has dragged the anchored media clip  1025  further towards left in such a way that the left edge (in-point) of the media clip has covered a portion of media clip  1035  as shown in this stage. In other words, the user has hovered media clip  1025  between the two media clips  1035  and  1040  in the central compositing lane  1045 . As a result, the media-editing application makes space between the two media clips  1035  and  1040  in the central compositing lane  1045  for the anchored media clip  1025 . 
     At stage  1020 , the user has dropped the anchored media clip  1025  (by releasing the mouse button, “tap” of a touchscreen, etc.) in the space previously created at stage  1015 . Consequently, the media-editing application places the media clip  1025  between the two media clips  1035  and  1040  in the central compositing lane  1045 . 
     F. Moving Anchored Clips Along Anchor Lanes 
       FIG.  11    illustrates an example of moving an anchored clip along an anchor lane in a timeline of a media-editing application. Specifically, this figure illustrates the GUI  1100  in three different stages  1105 ,  1110 , and  1115  to show that a preview display area  1185  displays the frame of a media clip to which an media clip  1130  is anchored. The GUI  1100  is similar to the GUI  100  described above by reference to  FIG.  1    in that the GUI  1100  includes a timeline  1180  and the preview display area  1185  which are similar to the clip browser  110  and the timeline  105 , respectively. 
     In some embodiments, an anchored media clip is represented as a rectangular shape. Each anchored media clip also has an anchor, which is represented as a pointer attached to the rectangular shape that connects the rectangular shape and a media clip representation displayed in the central compositing lane of a timeline. When a first media clip is anchored to a second media clip that is displayed in the central compositing lane, the anchor of the first media clip points to a position along the length of the second media clip. In some embodiments, the media-editing application displays a frame of the media clip represented by that position in the preview display area, when the first media clip is selected. 
     The operation of the GUI  1100  will now be described by reference to the three stages  1105 - 1115  that are illustrated in  FIG.  11   . In the first stage  1105 , the media-editing application displays two media clips  1170  and  1165  in the central compositing lane  1140  and two anchored media clips  1130  and  1135 . The first anchored media clip  1130  is anchored to the media clip  1165  in the central compositing lane  1140 . The preview display area  1185  does not display any frame as no media clip is selected and a playhead is intersecting none of the media clips. 
     The second stage  1110  illustrates that the user has selected the first anchored media clip  1130  in the anchor lane  1125  using a cursor (e.g., by clicking a mouse button, tapping a touchpad, or touching a touchscreen). The media-editing application indicates the selection by highlighting the border of the anchored media clip  1130  as shown. The user selects the anchored media clip  1130  as the media clip that the user wishes to move along the anchor lane. As shown, the preview display area  1185  displays the frame in the media clip  1165  to which the anchor of the media clip  1130  is pointing. 
     At stage  1115 , the user has dragged the anchored media clip  1130  towards right and dropped it (by releasing the mouse button, “tap” of a touchscreen, etc.) closer to the anchored media clip  1135 . As shown in stage  1115 , the position of the anchor of the anchored audio clip  1130  does not change by changing the position of the anchored clip. In other words, the anchor and the anchored clip will move along the anchor lane together and as one entity. Moreover, the preview display area  1185  is now displays a frame of the media clip  1165  to which the anchor  1175  is pointing. 
       FIG.  12    illustrates an example of moving multiple anchored clips along an anchor lane in a timeline of a media-editing application. Specifically, this figure illustrates the timeline  1200  in four different stages  1205 ,  1210 ,  1215 , and  1220  to show that the media-editing application allows a user of the application to move multiple anchored clips along different anchor lanes. The timeline  1200  is similar to the timeline  115  described above by reference to  FIG.  1   . The timeline  1200  includes a central compositing lane  1235 . 
     Some embodiments allow the user of the application to select two or more clips in different anchor lanes of the timeline  1200  to move together. This allows preserving the timing information between the selected anchored clips when the clips are placed in different positions along the timeline  1200 . 
     The operation of the timeline  1200  will now be described by reference to the four stages  1205 - 1220  that are illustrated in  FIG.  12   . In the first stage  1205 , the media-editing application displays two media clips  1250  and  1255  in the central compositing lane  1235 . In addition, the media-editing application displays a media clip  1240  is in the anchor lane  1225  above the central compositing lane  1235  and a media clip  1245  is in the anchor lane  1230  below the central compositing lane  1235 . The media clips  1240  and  1245  are anchored to the media clip  1250  in the central compositing lane  1235 . 
     The second stage  1210 , illustrates that a user has selected the anchored media clip  1245  in the anchor lane  1230  by using a cursor (e.g., by clicking a mouse button, tapping a touchpad, or touching a touchscreen). The selection is illustrated in some embodiments by a bolding of the border of the anchored media clip  1245 . The user selects the anchored media clip  1245  as one of the media clips that the user wishes to move along the anchor lanes. 
     The third stage  1215 , illustrates that the user has selected the anchored media clip  1240  in the anchor lane  1225  as the second selected anchored media clip by using a cursor (e.g., by clicking a mouse button, tapping a touchpad, or touching a touchscreen). The selection is illustrated by a bolding of the border of the anchored media clip  1240 . The user selects the anchored media clip  1240  as the second media clip that the user wishes to move along the anchor lanes. 
     At stage  1220 , the user has dragged the anchored media clips  1240  and  1245  towards the right and dropped them (by releasing the mouse button, “tap” of a touchscreen, etc.) close to the end of the second media clip in the central compositing lane  1235 . As a result, the media clips  1240  and  1245  are anchored to the media clip  1255  in the central composting lane  1235 . The relative positions of the two anchored media clips are not changed. 
     As illustrated, the user moves two anchored media clips along two different anchor lanes at the same time in this example. However, the user may move any number of anchored media clips (or portions of anchored clips) from multiple anchor lanes above the central compositing lane and multiple anchor lanes below the central compositing lane at the same time as well. As described above, the user may also move one or more anchored media clips from one position in the anchor lane to another position in the same anchor lane. 
     C. Duplicating Anchor Clips 
       FIG.  13    illustrates an example of duplicating anchored clips in anchor lanes of a timeline of a media-editing application. Specifically, this figure illustrates the timeline  1300  in four different stages  1305 ,  1310 ,  1315 , and  1320  to show that the media-editing application allows a user of the application to copy one or more anchored clips from a position in anchor lanes and paste them in a different position in the anchor lanes. The timeline  1300  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     Some embodiments allow the user to create duplicate copies of one or more media clips displayed in the timeline  1300  and place the duplicate copies of the clips in another location within the timeline  1300 . The media-editing application preserves relative timing information between two or more anchored media clips when the duplicate copies of them are placed in another location within the timeline. 
     The operation of the timeline  1300  will now be described by reference to the four stages  1305 - 1320  that are illustrated in  FIG.  13   . In the first stage  1305 , the media-editing application displays two media clips  1355  and  1360  in the central compositing lane  1335 . The media-editing application also displays a media clip  1340  in the anchor lane  1325  above the central compositing lane  1335  and a media clip  1345  in the anchor lane  1330  below the central compositing lane. The media clips  1340  and  1345  are anchored to the media clip  1250  in the central compositing lane  1335 . 
     The second stage  1310  illustrates that a user has selected and copied the anchored media clips  1340  and  1345  in the anchor lanes  1325  and  1330 , respectively. More detail of selecting a media clip is described above by reference to  FIG.  12   . The selection is illustrated in some embodiments by a bolding of the border of the anchored media clips  1340  and  1345 . In this example, the user selects the anchored media clips  1340  and  1345  as the two media clips that the user wishes to paste duplicate copies of them somewhere else in the anchor lanes. As it is mentioned above, the user has also copied these two clips at this stage. In order to copy an anchored clip, some embodiments provide a pop-up or pull-down menu or window (not shown) to receive a user input as to where the copy must be saved. In some such embodiments, a user also has the option to save the copy of the anchored media clip in other temporary storage (e.g., a clipboard). 
     The third stage  1315  illustrates that the user has selected a different spot on the anchor lane by using a cursor (e.g., by clicking a mouse button, tapping a touchpad, or touching, a touchscreen). In this example, the media-editing application allows the user to specify the position along the timeline  1300  to which to paste the duplicate copies of the media clips  1350  and  1345  by a skimming playhead  1351 . The skimming playhead is similar to the skimming playhead  330  described above by reference to  FIG.  3   . 
     In the fourth stage  1320 , the user has pasted the anchored media clips  1340  and  1345  at locations in the timeline  1300  where the user had previously specified in the third stage  1315 . As shown in this stage  1320 , the two anchored media clips  1340  and  1345  are copied onto the new locations in the anchor lanes with exactly the same relative positions they had in their original locations with respect to the central compositing lane  1335 . In order to paste an anchored clip, some embodiments provide a pop-up or pull-down menu or window (not shown) to receive a user input as to where the saved copy must be pasted. In some embodiments, the media-editing application also provides an option to paste the saved copy of the anchored media clip from the clipboard. 
     While the above example illustrates copying two anchored media clips in two different anchor lanes at the same time and then pasting them at the same time, some embodiments allows the user to copy and paste any number of anchored media clips from the anchor lane above the central compositing lane and the anchor lane below the central compositing lane (not shown) at the same time as well. The user may also copy and paste (not shown) one or more anchored media clips from one position in the anchor lane to another position in the same anchor lane. 
     H. Snapping Media Clips 
       FIG.  14    illustrates an example of horizontal snapping of two media clips displayed in a timeline of a media-editing application. Specifically, this figure illustrates the timeline  1400  in three different stages  1405 ,  1410 , and  1415  to show that the media-editing application snaps a media clip  1435  to a media clip  1430  as the user moves the media clip  1435  within a certain distance from the media clip  1430 . The timeline  1400  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     In some embodiments, the media-editing application snaps a first media clip to a second media clip when the user drags (e.g., by a cursor operation) the first media clip close to the second media clip from either side of the second media clip. When the user moves the first media clip from the right side of the second media clip, the media-editing application snaps the left edge of the first media clip to the right edge of the second media clip. Conversely, when the user moves the first media clip from the left side of the second media clip, the media-editing application snaps the right edge of the first media clip to the left edge of the media clip. The media-editing application applies this snapping feature to any types of clips in any lanes (central compositing lanes, anchor lanes, etc.) that may be displayed in the timeline. 
     As will be described further below, some embodiments may move away the second clip to make room for the first media clip. Also, some embodiments may temporarily superimpose the second clip to prompt for replacement options. Therefore, the media-editing application of some embodiments uses a set of criteria to determine an operation to perform. The set of criteria may include the velocity of the first media clip at which the second media clip is moving to the, types of clips the first and second clips are, the direction in which the first media clip is approaching the second media clip, the origin (e.g., a clip browser, a timeline, etc.) from which the first media clip is moving, etc. 
     The operation of the timeline  1400  will now be described by reference to the three stages  1405 - 1415  that are illustrated in  FIG.  14   . In the first stage  1405 , the media-editing application displays two anchored media clips  1430  and  1435  in two different positions in the anchor lane  1420 . The user has selected the anchored media clip  1435 . In some embodiments, the user of the media-editing application may perform this selection by clicking a mouse button, tapping a touchpad, or touching a touchscreen. The selection is shown in some embodiments by a bolding of the border of the anchored media clip  1435 . The user selects the media clip  1435  to move it towards the media clip  1430  in the anchor lane  1420 . 
     The second stage  1410  illustrates that the user has dragged the anchored media clip  1435  towards the left and close to the media clip  1430 . When the distance between two media clips drops below a certain threshold distance, the media-editing application determines an operation to perform based on a set of criteria. 
     At stage  1415 , the user has released the anchored media clip  1435  (by releasing the mouse button, “tap” of a touchscreen, etc.) when the distance between the two clips (e.g., the distance between the upper right corner of the media clip  1430  and the upper left corner of the media clip  1435 ) is smaller than a certain distance. Using the set of criteria, the media-editing application determines that the operation to perform is snapping the two media clips and then snaps the media clip  1435  to the right edge of the media clip  1430 . As a result, the two media clips become two contagious clips as shown. 
     I. Vertically Swapping Anchored Clips 
       FIG.  15    illustrates an example of vertical swapping of two anchored media clips in two different anchor lanes in a timeline of a media-editing application. Specifically, this figure illustrates a timeline  1500  in three different stages to show that the media-editing application allows a user of the application to vertically swap an anchored clip  1550  with an anchored clip  1545 . The timeline  1500  is similar to the timeline  105  described above by reference to  FIG.  1   . 
     As described above, an anchored clip&#39;s media content is composited with (e.g., overlay, superimpose, mix, etc.) the media content of the media clip in a compositing lane. When there are multiple anchored dips at a position along the timeline  1500 , the media content of an anchored clip in an upper anchor lane takes the priority over the media content of a media clip in a lower lane in some embodiments. By allowing vertical swapping, the media-editing application provides a simple way of changing priorities of the anchored clips. 
     The operation of the timeline  1500  will now be described by reference to the three stages  1505 - 1515  that are illustrated in  FIG.  15   . In the first stage  1505 , the media-editing application displays three anchored media clips  1540 - 1550  in three different anchor lanes  1520 - 1530 , respectively. The user has selected the anchored media clip  1550  in the anchor lane  1530  using a cursor (e.g., by clicking a mouse button, tapping a touchpad, or touching a touchscreen). The selection is illustrated in some embodiments by a bolding of the border of the anchored media clip  1550 . The user has selected the anchored media clip  1550  to swap with the anchored media clip  1545  in the anchor lane  1525 . 
     The second stage  1510  illustrates that the user has dragged the anchored media clip  1550  up and towards the anchored media clip  1545  in the anchor lane  1525 . The media-editing application overlays the media clip  1545  with the media dip  1550 . Based on a set of criteria, the media-editing application determines an operation to perform. 
     In the third stage  1515 , the user has released the anchored media clip  1550 . Using, the set of criteria, the media-editing application determines that it will swap the two media clips vertically and the swaps the two media clips. Accordingly, the compositing priorities of the two media clips have been switched as well. 
     J. Live Drag 
       FIG.  16    illustrates a timeline  1600  of a media-editing application that displays results of editing operations as the editing operations are being performed. Specifically,  FIG.  16    illustrates the timeline  1600  in four different stages  1605 - 1620  to show that the timeline  1600  displays media clip  1625  being pushed up to another anchor lane as media clip  1625  is dragged towards the media clip  1630 . The timeline  1600  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     As described above, the media-editing application of some embodiments allows the user to edit a media presentation by moving a media clip from one location to another location within a timeline or from an area out of the timeline into the timeline. For instance, the user can drag a media clip from a clip browser (not shown) into a central compositing lane or to a location occupied by an anchored clip in an anchor lane. Some embodiments show the result of editing operation performed by moving media clips as the operations are being performed. In other words, when the user moves media clips within the timeline or into the timeline, the timeline of these embodiments display movement of the media clips. 
     When a media clip is dragged into the central compositing lane and collides with the media clips displayed in the lane, the media clips in the central composting lane move along the central compositing lane, whereas anchored clips may also get pushed up or down. The up or down movement of the anchored clips in some embodiments can be viewed as dynamic creation of anchor lanes. For instance, when an anchored clip collides with a media clip that is being dragged, the anchored media clip moves to a higher level to make space for the dragged clip. 
     In some embodiments, the media-editing application displays a visual indication between the media clips as a media clip is dragged and moved over the region of the timeline  1600 . This visual indication helps the user to identify the media clips between which the user may wish to place the media clip being dragged. 
     In the first stage  1605 , the timeline  1600  displays the media clips  1625  and  1630  in the anchor lane  1640 . These two clips are anchored off the media clips displayed in the central compositing lane  1635 . In the second stage  1610 , the user selects (e.g., via a clicking operation) the anchored media clip  1630  to drag it to the left. 
     In the third stage  1615 , the user drags the media clip  1630  to a location close to the media clip  1625 . As the media clip  1630  is dragged near the media clip  1625 , the timeline  1600  moves the media clip  1625  upward so as to make room for the media clip  1630 . In the fourth stage, the user drags the media clip  1630  to a location that was formerly occupied by the media clip  1625 . The timeline  1600  moves the media clip  1625  above the media clip  1630 . As a result, timeline  1600  has created another anchor lane  1650  on top of the anchor lane  1640 . 
       FIG.  17    conceptually illustrates a process  1700  of some embodiments for rearranging positions of media clips in a timeline while a media clip is being dragged over or extended into different regions of the timeline. The process  1700  is performed by a media-editing application. The process starts when the media-editing application displays a timeline. 
     The process begins by determining (at  1705 ) whether a media clip is selected for editing. As described above, a selection of a media clip for editing can be accomplished in a variety of ways. For instance, a user can select a media clip in a timeline by clicking on a portion of the media clip. In some embodiments, the process determines that a media clip is selected for editing when only part of a media clip is selected. For instance, the process determines that a media clip is selected for editing when either side edge of the media clip is selected for trimming or extending. Also, the process determines that a media clip is selected for editing when a media clip is being brought from out of the timeline. For instance, a media clip that is being dragged into the timeline is deemed selected by the process. 
     When the process determines (at  1705 ) that no media clip is selected for editing, the process loops back to  1705  until a selection is made. Otherwise, the process determines (at  1710 ) whether the selected media clip has moved within a threshold distance from a second media clip. Different embodiments determine whether the selected media clip has moved within the threshold distance differently. In some embodiments, the process draws an invisible shape around the second media clip. The process in these embodiments determines that the selected media clip is within the threshold distance from the second media clip when any part of the selected media clip comes within the enclosing shape. In some cases, the selected media clip comes within the enclosing shape when the whole media clip is selected and dragged. In other cases, the selected media clip comes within the enclosing shape when the selected media clip is extended into the enclosing shape. The process in other embodiments places invisible markers throughout a media clip&#39;s border and measures the distance between two media clips by measuring the shortest distance between any two markers (i.e., one for each media clip) of the two media clips. 
     When the process determines (at  1710 ) that the selected media clip is within a certain threshold distance from another media clip, the process proceeds to  1720  which will be described further below. Otherwise, the process determines (at  1715 ) whether the selected media clip is deselected. The user may deselect a selected media clip in a variety of different ways. For instance, the user can deselect a selected media clip by releasing a mouse button or removing a finger from a touch screen, etc. 
     When the process determines (at  1715 ) that the selected media clip has not been deselected, the process loops back to  1710  to determine the selected media clip has been moved within a threshold distance of a second media clip. Otherwise, the process places (at  1725 ) the media clip at the location in the timeline where the media clip has been deselected. In some cases, the location in the timeline where the process places the media clip may be the same location as the selected media clip&#39;s initial location. The process then loops backs to  1705  to determine whether there is a media clip selected for editing. 
     When the process determines (at  1710 ) that the selected media clip has been moved within a threshold distance from the second media clip displayed in the timeline, the process determines (at  1720 ) whether the selected media clip has been within the threshold distance from the second media clip for longer than a certain threshold period of time. In some embodiments, the process uses different threshold value for different cases. For instance, the process may use different threshold period for cases when the selected media clip is touching or at least partly overlapping the second media clip and for cases when the selected media clip is not in contact with another media clip. 
     When the process determines (at  1720 ) that the selected media clip has been within the threshold distance from the second media clip longer than the threshold period of time, the process proceeds to  1735  which will be described further below. Otherwise, the process determines (at  1740 ) whether the selected media clip has been deselected. When the process determines (at  1740 ) that the media clip has been deselected, the process places (at  1745 ) at the location where the selected media clip was deselected. The process also identifies all other media clips affected by the placement of the selected media clip at the new location of the selected media clip. The affected media clips may include the second media clip. The process changes the locations of those affected media clips to new locations if necessary. For instance, the process may push the second media clip up to another anchor lane. The affected media clips may include other media clips whose positions are affected by the bumped up media clip. In this manner, the placement of the selected (now deselected) media clip may cause a series of movements of some of the media clips in the timeline. 
     When the process determines (at  1740 ) that the selected media clip has not been deselected, the process determines (at  1750 ) whether the selected media clip has moved away from the second media clip such that the selected media clip is no longer within the threshold distance form the second media clip. When the process determines (at  1750 ) that the selected media clip has been moved away, the process loops back to (at  1710 ) to determine whether the selected media clip has moved within a threshold distance from a third media clip. 
     When the process determines (at  1750 ) that the selected media clip has not been moved away from the second media clip further than the threshold distance, the process loops back to  1720  to determine whether the selected media clip has been within the threshold distance from the second media clip longer than the threshold period of time. 
     When the process determines (at  1720 ) that the selected media clip has been moved within the threshold distance from the second media clip and has been there for longer than the threshold period of time, the process (at  1735 ) identifies the media clips that are affected by the movement of the selected media clip and displays the affected media files in different locations in the timeline if necessary. As described above, the process may move the second media clip to another location and the movement of the second media clip may affect other media clips that were placed near or adjacent to the second media clip. Placing affected media clips will be described in detail further below by reference to  FIGS.  18  and  19   . 
     Process  1700  then determines (at  1755 ) whether the selected media clip has been deselected. When the process determines that the selected media clip has been deselected, the process places (at  1760 ) the selected media clips and the affected media clips at the locations to which the process has moved (at  1735 ) them. Otherwise, the process determines (at  1765 ) whether the selected media clip has moved away from the second media clip such that the selected media clip is no longer within the threshold distance from the second media clip. 
     When the process determines (at  1765 ) that the selected media clip has not been moved away from the second media clip, the process loops back to  1755  to determine whether the selected media clip is deselected. Otherwise, the process puts back the affected media clips back to the locations where they had been before the process moved (at  1735 ). The process puts (at  1770 ) them back because the selected media clip was not deselected (i.e., not released) while it was within the threshold distance from the second media clip. The process then loops back to  1710  to determine whether the selected media clip has moved within a threshold distance of a third media clip. 
     One of ordinary skill in the art will recognize that process  1700  is a conceptual representation of the operations used to arrange the media clips in a timeline as one of media clip is being moved within a timeline. The specific operations of process  1700  may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. For instance, the operations the process  1700  performs are described in the context of one selected media clip being moved around the timeline and coming close to one other media clip. However, the process may perform these operations for other combinations of media clips. For instance, the media clip being moved around in the timeline could be a combination of two or more media clips that are selected together. Also, such media clip may be a selected range over one or media clips. 
       FIG.  18    conceptually illustrates a process  1800  of some embodiments for placing media clips in a timeline when a media clip has moved to a new position in the timeline. The process  1800  is performed by a media-editing application. In some embodiments, process  1800  is performed whenever the media-editing application determines that a moving media clip has moved to a new location in the timeline or has been in a location that is closer than a threshold distance from another media clip for longer than a threshold period of time. Process  1800  will be described by reference to  FIG.  19   , which illustrates an example of placing media clips in a timeline  1900  in six different stages  1905 - 1930 .  FIG.  19    illustrates media clips A, B, C, D, E and F. The media clips A, B, and C are in spine  1901 . The media clip D is initially anchored to the media clip A and spans part of the media clips A and B horizontally. The media clip E is anchored to the media clip B and spans part of the media clip B horizontally. The media clip F is a moving media clip. That is, the media clip F is being moved into a new location in the timeline  1900 . Process  1800  starts when a media clip has moved to a new location in the timeline or has been in a location in the timeline that is closer than a threshold distance from another media clip for longer than a threshold period of time. 
     Process  1800  begins by identifying (at  1805 ) media clips that are affected by the moving clip. As described above, the affected clips are those clips that the media-editing application moves as a result of having moved the moving piece to its new location. As shown at stage  1901  in  FIG.  19   , the media clip F has moved to a new location such that the media clip F partially overlaps the media clip E in the timeline  1900 . Since the media-editing application of some embodiments does not allow two anchored clips to overlap each other within one anchor lane, the media-editing application moves the media clip E to another location in the timeline  1900 . As such, the media clip E is a media clip affected by the movement of the media clip F. The media clip D is not affected because it does not have to move. The height of the media clip D is larger than that of another media clip in the timeline  1900  because the media clip D has its audio and video portion visually separated in this example. 
     Process  1800  then selects (at  1810 ) next bottom clip. A bottom clip is a clip among the affected clips and the moving clip to be placed closest to the spine of the timeline. In some embodiments, the process finds the bottom clip using the lane numbers of the lanes that the affected media clips are occupying before the moving clip has moved. Lane numbers are described further below by reference to  FIG.  33   . At stage  1905  in  FIG.  19   , the media-editing application identifies the media clip F as the bottom clip. This is because the media clip E will be moved to another anchor lane above the lane that the media clip E currently occupies. As described above, an anchored media clip retains its temporal position relative to a media clip in the spine to which the anchored clip is anchored. Thus, in order to retain that relative temporal position of the media clip E with respect to the media clip B and to avoid overlapping the media clip E with the media clip F, the media-editing application of some embodiments moves the media clip E into another anchor lane. The media-editing application does not move the media clip E closer to the spine  1901  because the media clip D is already occupying part of the space below the media clip E. 
     Process  1800  then defines (at  1815 ) available spaces to place the bottom clip. In some embodiments, the process first defines all available spaces based on the positions of the side edges of the affected media clips and the moving media clip. For instance, as shown at stage  1910  in  FIG.  19   , the media-editing application defines rectangular space  1911  (depicted as a dotted rectangle) bounded by the horizontal position of the left edge of the media clip E and the horizontal position of the right edge of the media clip D. The media-editing application defines rectangular space  1912  (depicted as a dotted rectangle) bounded by the horizontal position of the right edge of the media clip D. At stage  1915 , the media-editing application divides the  1911  space  1911  into two spaces  1915  and  1916  based on the horizontal position of the left edge of the media clip F. The media-editing application defines these spaces  1911 ,  1912 ,  1915 , and  1916  in order to find an anchor lane that is closest to the spine  1901  and that can include the entire length of the media clip F (i.e., the current bottom clip) without moving the media clip F horizontally. 
     Next, process  1800  finds (at  1820 ) a location in which to place the current bottom clip and places the current bottom clip at the location. In some embodiments, the process finds lowest possible horizontal span that can include the entire width of the current bottom clip. For instance, as shown at stage  1915  in  FIG.  19   , the space  1912  alone cannot contain the entire width of the media clip F horizontally. Together with the space  1916 , the space  1912  can contain the entire width of the media clip F. As shown, the space  1916  is above the media clip D. Thus, the media-editing application places the media clip F above the media clip D. 
     Process  1800  then determines (at  1825 ) whether all clips that need to be placed have been placed. That is, the process determines whether all of the affected clips as well as the moving clip have been placed in the timeline. When the process determines (at  1825 ) that there are more clips to place, the process loops back to  1810  to select the next bottom clip to place. Otherwise, the process ends. As shown at stage  1920  in  FIG.  19   , the media editing application has not placed the media clip E yet. The media-editing application defines the space  1915  and a space  1921 . The space  1921  is defined above the media clip F and bounded by the both side edges of the media clip F. 
     At stage  1925  in  FIG.  19   , the media-editing application divides the space  1921  into spaces  1926  and  1927  based on the horizontal position of the right edge of the media clip E. As shown, the space  1915  alone cannot contain the entire width of the media clip E horizontally. Together with the space  1926 , the space  1915  can contain the entire width of the media clip F. As shown, the space  1926  is above the media clip F. Thus, at stage  1930 , the media-editing application places the media clip E above the media clip F. 
     One of ordinary skill in the art will recognize that process  1800  is a conceptual representation of the operations used to arrange the media clips in a timeline as one of media clip is being moved within a timeline. The specific operations of process  1800  may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. 
     III. Live Edit 
       FIG.  20    conceptually illustrates a GUI  2000  of a media-editing application that displays the results of editing operations in a viewer  2020  as the editing operations are being performed. Specifically,  FIG.  29    illustrates the GUI  2000  in three different stages  2005 - 2015  as a user of the application moves an anchored clip  2025  along a timeline  2030  such that it intersects with the playhead that is moving through the timeline. The GUI  2000  is similar to the GUI  100  described above by reference to  FIG.  1    in that the GUI  2000  includes a clip browser  2040 , a viewer  2020 , and a timeline  2030  which are similar to the clip browser  110 , the timeline  115 , and the viewer  110 , respectively. 
     The media-editing application of some embodiments allows the user to edit a media presentation by moving a media clip from one location to another location within a timeline or from an area out of the timeline into the timeline. For instance, the user can drag a media clip from the clip browser  2040  into a central compositing lane  2045  or into an anchor lane. Some embodiments show the composite result of the editing operation performed by moving media clips as the operations are being performed. More specifically, the media-editing application of some embodiments displays a composite image represented by a point along the timeline  2030  in the viewer  2020  as the playhead  2035  moves to the point that intersects with a media clip that is being moved. 
     As the playhead  2035  moves along the timeline  2030  (i.e., as the media-editing application playbacks the media presentation), the media-editing application displays a composite frame of the media presentation represented by a point along the timeline  2030  at which the playhead is positioned currently. When any part of a media clip occupies a point along the timeline  2030  at the moment the playhead  2035  is passing the point, the media-editing application will factor that media clip into the composite image displayed for that point. When a media clip is in an anchor lane above the central compositing lane, the output image will be that of the anchor lane (unless there is a blend operation defined between the two frames). 
     In the first stage  2005 , the timeline  2030  displays an anchored media clip  2025  and media clips  2026 - 2029  within the central compositing lane  2045 . At this point, the media-editing application is playing back the media presentation and thus the playhead  2035  is moving to the right through the timeline  2030 . The playhead  2035  currently is in the middle of the media clip  2026 , and thus the preview display area  2020  displays an image of the media clip  2026  that corresponds to the portion of the media clip at which the playhead is currently located. 
     In the second stage  2010 , the user has selected the media clip  2025  and is dragging the media clip  2025  to the left such that the playhead that is moving to the right intersects with the media clip  2025 . Because the clip  2025  is in the anchor lane, the preview display area  2020  displays the image from this clip, rather than media clip  2028  in the central compositing lane. At this point, the playhead  2035  is continuing to move to the right to play the presentation. In some embodiments, as soon as the playhead intersects the left edge (in-point) of clip  2025 , the playback image displayed in the preview display area changes to that of the anchored clip  2025 . 
     In the third stage  2015 , the user is dragging the media clip  2025  to the right along with the playhead  2035 . As in the stage  2010 , the media-editing application displays a frame from the media clip  2025  in the preview display area  2020 . This is a different frame than shown at stage  2010 , as the playhead is located over a different portion of the clip  2025 . In theory, a user could drag the anchored clip to the right at the same rate as the playhead, and have the same image displayed in the preview display area. 
     The media clip  2025 , therefore, has been moved back and forth along the timeline  2030  as shown in the stages  2010 - 2015 . As the clip  2025  has been moving back and forth, the primary playhead has intersected with different parts of the clip  2025  at different points along the timeline  2030 . The media-editing application has been reflecting the composite frames resulted from these intersections caused by the movement of the media clip  2025 . 
       FIG.  21    conceptually illustrates a process  2100  for incorporating edits into playback of a video sequence in real-time. As shown, the process  2100  begins by receiving (at  2105 ) a project playback command. In some embodiments, the user commands the media-editing application to play back the contents of the timeline. The playback may start at the current location of the playhead in the timeline, or at the beginning of the project (i.e., time=0). 
     The process moves (at  2110 ) the playhead in the timeline. The media-editing application displays the movement of the playhead at a rate representative of real-time. That is, in a particular amount of actual time, the playhead moves over a portion of the timeline representative of that particular amount of time. In this process, the operation  2110  indicates a movement of one image (i.e., 1/24 th  of a second for 24 fps video) in the timeline. 
     The process also identifies (at  2115 ) the next image from the project data. In some embodiments, the project data is kept up to date with updates to the project as the user modifies the clips in the project. When playing back a project (i.e., a media presentation), the application makes sure that the image being displayed is the correct image for the most up-to-date version of the project data. In some embodiments, when the project data changes, the process receives an indication that this change has been made and retrieves the new project data. These changes may include movement of clips in the timeline, adding clips to the timeline, removing clips from the timeline, adding effects to clips, etc. 
     With the image identified, the process  2100  performs (at  2120 ) operations required to display the image in the preview display area. This may involve a disk read operation, decode operation, any graphics processing operations to generate a proper format image or combine images, etc. In some embodiments, the image will have already been generated by a background rendering process or by pre-rendering during playback and at this stage the application just reads the generated image (e.g., from memory) and outputs the image. 
     The process then determines (at  2125 ) whether any more images need to be played back. If the user pauses the playback, then (at least temporarily) the application can cease outputting images. In addition, if the playhead reaches the end of the timeline, then playback will cease unless the user has set the application to playback the timeline in a continuous loop. When no more images remain, the process  2100  ends. 
     When additional images remain, the process determines (at  2130 ) whether any user edits to the timeline are being received. These edits may be the addition of effects, transitions, titles, etc., the movement of clips, trimming of clips, removal of clips, or other edits that affect the project displayed in the timeline. 
     When no such edits are received, the process returns directly to  2110  to move the playhead and identify the next image. However, when edits are received, the process displays (at  2135 ) a modified timeline and modifies (at  2140 ) the project data. The modified display may involve the movement of a clip, the indication of an effect, etc. With the modification performed, the process proceeds to  2110  to move the playhead and identify the next image. 
     IV. Editing Tools 
     A. Multi-Track Editing 
       FIG.  22    conceptually illustrates an in-line multi-tracked editing tool for a timeline of a media-editing application. Specifically, this figure illustrates in four different stages  2205 - 2220  to show activating the in-line multi-tracked editing tool in a timeline  2200 . The timeline  2200  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     As described above, a media clip in some embodiments include different types of media content. For instance, an audio and video clip has both video and audio content. In some such embodiments, a media clip includes different “tracks” for each type of media content. For instance, an audio content of an audio clip may include several tracks for several audio channels. Likewise, a video content of a video clip may include several tracks for a foreground video and a background video. 
     The media-editing application of some embodiments provides a multi-tracked editing tool. This multi-track editing tool is an in-line tool. That is, the media-editing application opens this multi-tracked editing tool within the timeline  2200  in some embodiments. This multi-tracked editing tool opens different tracks contained in a media clip in different lanes to allow the user to edit individual tracks of the media clip independently. In some embodiments, the multi-tracked editing tool opens different tracks of a media clip in a central compositing lane and a set of anchor lanes. Each lane will include a track of a media clip in these embodiments. In some embodiments, the media-editing application does not display in the tool any other media clips that were displayed in the timeline before the tool was opened. 
     The first stage  2205  shows the timeline  2200  before the media-editing application opens a multi-tracked editing tool for a media clip. As shown, the central compositing lane  2230  displays two media clips  2235  and  2240 . The second stage  2210  illustrates the selection of the media clip that the user of the media-editing application wants to edit with the multi-tracked editing tool. The user selects a media clip through a cursor click operation, through a keystroke, through a selection from a pull-down menu. The user has selected the media clip  2240  in the timeline  2200 . 
     In the third stage  2215 , the media-editing application displays a drop-down menu  2245  that includes a selectable item which, when selected, will cause the media-editing application to display the multi-tracked editing tool for editing the selected media clip  2240 . The user selects (e.g., by a click operation) the item. The fourth stage  2220  illustrates that upon receiving the selection, the media-editing application opens up the selected media clip  2240  in the in-line multi-tracked editing tool. As shown, the lanes  2260  and  2270  display the individual video and audio tracks that make up the media clip  2240 . 
     B. Precision Editor 
       FIG.  23    conceptually illustrates an example of an in-line precision editing tool for a timeline of a media-editing application. Specifically, this figure illustrates a timeline  2300  five different stages  2305 - 2320  to show the modification of the transition point between media clips  2332  and  2334  in a timeline  2300  using a precision editing tool of some embodiments. The timeline  2300  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     The media-editing application of some embodiments provides a precision editing tool that allows a user of the application to modify the point at which one clip transitions into the next, trimming or extending frames at the end of one clip and at the beginning of the next clip in the same magnified view. The precision editing tool in some embodiments displays both clips on either side of a transition such that the unused frames (i.e., available media content of the source media files) from both clips. In this manner, the precision editing tool displays how the edits affect the transition from one clip to the next. In some embodiments, this precision editing tool is an in-line tool. That is, the media-editing application opens this multi-tracked editing tool within the timeline  2300 . 
     The first stage  2305  shows the timeline  2300  before the user performs a transition modification operation between two media clips  2330  and  2335  using a precision editing tool. The timeline  2300  displays media clips  2330  and  2335  in the central compositing lane  2340 . 
     The second stage  2310  shows the activation of the precision editing tool in the timeline  2300 . The media-editing application provides various ways to activate the tool. For instance, the user may click a point along the timeline where two media clips  2330  and  2335  meet. In some embodiments, the user of the media-editing application may activate the precision editing tool by a selection on a pull-down menu, by a keystroke, and a selection from a pop-up menu, etc. after selecting the adjacent edges of the two media clips. As shown, the media-editing application splits the central compositing lane  2340  into two lanes  2350  and  2355 . 
     The top lane  2350  displays the outgoing media clip  2330  as well as the additional media content beyond the out-point of the media clip  2330 . As described above, the additional media content beyond the out-point of a media clip is in the source media clip of the media clip. The media-editing application displays a vertical line at the current out-point of the media clip  2330  as shown. The vertical line separates the media clip  2330  and the additional media content. 
     The bottom lane  2355  displays the incoming media clip  2335  as well as the additional media content beyond the in-point of the media clip  2335 . The media-editing application displays a vertical line at the current in-point of the media clip  2335 . The vertical line separates the media clip  2335  and the additional media content. The vertical line in the bottom lane  2355  and the vertical line in the top lane are the same vertical line in some embodiments as shown. The user has also selected (e.g., by a click operation) the out-point of the outgoing media clip  2330  to push out the out-point and include more frames in the media clip. The media-editing application highlights the bracket  2370  to indicate the selection of the out-point of the media clip  2330 . 
     The third stage  2315  shows the movement of the edge  2370  that adds frames at the end of the outgoing media clip  2330 . The user pushes out the out-point of the media clip  2330  by dragging the edge  2370  of the media clip  2330  to the right to include additional frames to the media clip  2330  from the source media clip. The vertical line that separates the media clip  2330  and the additional media content has moved to further right from the position where it was in the second stage  2315 . The media-editing application has also moved the outgoing media clip  2335  and its additional available media content to the right along with the vertical line as the vertical line is moved to the right. The position of the vertical line with respect to the media clip  2335  and the additional content for the clip  2335  did not change to indicate that the in-point of the media clip  2335  did not change. 
     The fourth stage  2320  shows that upon the user&#39;s completion in adjusting the transition point between two media clips using the precision editing tool, the top track and the bottom track collapse back into one central compositing lane  2340 . The user may indicate his completion in editing the transition point by double clicking on the screen, making a selection on a pull-down menu, entering, a keystroke, etc. As shown, the top and bottom tracks  2350  and  2355  have collapsed back into the central compositing lane  2340  for one continuous composite presentation upon the user&#39;s signal. The central compositing lane the media clips  2330  and  2330  in such a way to reflect the edit that was made through the precision editing tool. That is, the media clip  2340  has been extended and the media clip has rippled (i.e., pushed to the right along the timeline  2300 ) 
       FIG.  24    illustrates an example of the movement of an anchored clip in the middle of a transition modification operation (i.e., while the precision editing tool is in operation). Specifically, this figure illustrates a timeline  2400  in four different stages  2405 - 2420  that the media-editing application allows the user to move an anchored clip that is anchored to a media clip displayed in the precision editing tool. The timeline  2400  is similar to the timeline  2300  described above in  FIG.  23   . 
     As described above, a central compositing lane splits into two lanes (i.e., a top lane and a bottom lane) at the point of transition between two clips to allow the user to trim or extend the two media clips. In some embodiments, the media-editing application displays anchor lanes when any exists and allows the user to edit any anchored clips in the displayed anchored lanes. 
     The first stage  2405  shows the timeline  2400  before the user performs a transition modification operation between two media clips. The timeline  2400  displays two media clips  2425  and  2430  in the central compositing lane  2435  and an anchored clip  2440  in an anchor lane  2445 . The user selects (e.g., by a click operation) the neighboring edges of the media clips  2425  and  2430  as indicated by the highlighted brackets. A user of the media-editing application may select the neighboring edges (i.e., the edit point  2450 ) by hovering the cursor at the transition point, by performing a keystroke, etc. 
     In the second stage  2410 , the media-editing application activates the precision editing tool. The media-editing application splits the central compositing lane  2435  of the timeline  2400  into two lanes  2455  and  2460 . 
     The third stage  2415  illustrates a selection of the anchored clip  2440  while the precision editing tool is in operation. The user selects the anchored clip by performing a cursor controller operation, by performing a keyboard operation, by selecting through a pull-down menu, etc. The media-editing application highlights the border to indicate the selection of the anchored clip  2440  in the anchor lane  2445 . 
     The fourth stage  2420  illustrates a movement of the anchored clip while the precision editor is still in operation. The user moves the anchored clip  2440  by dragging the selected clip across the anchor lane, by incrementing the position of the anchored clip using numeric entry, by keystroke, etc. 
     C. Editing Tools for Transition 
       FIG.  25    illustrates an example of adjusting a transition between two media clips in a timeline  2500  of a media-editing application. Specifically, this figure illustrates the timeline  2500  in four different stages  2505 - 2520  to show that the timeline displays a transition that becomes transparent as the transition is being adjusted.  FIG.  25    illustrates media clips  2525  and  2530  and a transition  2535 . The timeline  2500  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     A transition effect is an effect used to impact the transition from one media clip of a media presentation to the next media clip. There are many types of transition effects well known in the art. A common type of transition effect is a fade-out effect where the content of the outgoing media clip (i.e., the first clip of the two consecutive clips) gradually fades out as the content of the incoming media clip (i.e., the second clip of the two clips) gradually fades in. 
     To apply a transition effect between two adjacent media clips, both media clips must have additional media content that overlap past the edit point in some embodiments. That is, the incoming media clip has to have media content before its in-point and the outgoing media clip has to have media content beyond its out-point. The media-editing application uses these additional media contents to show the transitional effect instead of an abrupt cut between the two media clips. In the case of a fade-out, the additional media content of the incoming media clip starts to fade in before the clip&#39;s in-point (i.e., before the outgoing clip&#39;s out-point). Likewise, the additional media content of the outgoing media clip keeps fading out beyond the clip&#39;s out-point (i.e., beyond the incoming clip&#39;s in-point). 
     The timeline  2500  in some embodiments displays a transition as a rectangle between two media clips as shown in the second stage  2510  of this figure. In some embodiments, the media-editing application allows the user of the media-editing application to adjust the transition by manipulating the rectangle. For instance, the media-editing application allows the user to grab either side edges of the rectangle to adjust the points in time at which the incoming media clip starts to fade in or the outgoing media clip finishes fading out. The media-editing application may also allow the user to perform a rolling edit (i.e., adjusting the in-point of the incoming clip and the out-point of the outgoing media clip at the same time) by grabbing and dragging a middle portion of the rectangle. 
     When a transition is applied between two consecutive media clips, the media-editing application in some embodiments covers portions of the two media clips with the rectangle such that the covered portions are not visible in the timeline  2500 . In some such embodiments, the media-editing application displays the rectangle transparently such that each of the two media clips is affected when the transition effect is adjusted. The media-editing application determines whether one or both of the two media clips should be made visible as well as which of the two media clips should be made visible. The media-editing application determines this based on the position within the transition effect  2535  on which the user performs a click operation. For instance, when the user selects the right side edge of the transition  2535  to move it, the timeline  2500  displays the transition  2535  transparently so that the audio and video portions of the incoming media clip are visible to the user as shown in the third stage  2515  of this figure. When the user selects the left side edge of the transition  2535  to move it, the timeline  2500  makes the audio and video portions of the outgoing media visible through the transition  2535 . When the user selects a middle portion of the  2535 , the timeline  2500  makes the audio and video portions of both media clips to show the edit point between the two clips. The timeline  2500  may also provide a set of key commands to allow the user to make the transition transparent. 
     In the first stage  2505 , the timeline  2500  displays the media clips  2525  and  2530 . The user may select these two clips to apply a transition effect between them. The user selects these two clips and a transition effect to apply between them in many different ways that the media-editing application provides. For instance, the user may select these two clips via click operations and select a fade-out from a drop-down menu. 
     In the second stage  2510 , the user places a transition effect (e.g., a fade-out) that the user has selected between the media clips  2525  and  2530 . The user selects the right edge  2545  of the transition effect  2535  by a click operation. The timeline  2500  in some embodiments highlights the right edge  2545  of the transition to indicate the selection. 
     In the third stage  2515 , the user starts to drag the selected edge  2545  of the transition to the right. The timeline  2500  displays the transition  2535  transparently and makes the video portion of the media clip  2525  visible through the transition  2535 . In the fourth stage  2520 , the user has dragged the right edge  2545  of the transition further to the right and the video portion of the media clip  2525  shows the frames from the additional media beyond the initial in-point of the media clip. 
       FIG.  26    illustrates an example of adjusting a transition between two media clips in a timeline  2600  of a media-editing application. Specifically, this figure illustrates the timeline  2600  in four different stages  2605 - 2620  to show that the audio content and video content of the two media clips can be separately adjusted.  FIG.  26    illustrates media clips  2625  and  2630  and a transition  2635 . The timeline  2600  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     As described above, a media clip in some embodiments contains one or more types of media content (e.g., audio, video, text, image, etc.). When a transition is applied between two adjacent media clips in the timeline  2600  of some embodiments, the media-editing application allows the user to adjust the transition such that the adjustment affects all types of media content that the two media clips have at the same time. For instance, the timeline  2600  allows the user to drag the right side edge of a transition to adjust the point in time at which both the audio and video content of the outgoing media clip finish fading out. In some such embodiments, the timeline  2600  also allows the user to adjust different types of media contents separately. For instance, the timeline  2600  allows the user to adjust the audio contents of the two media clips without affecting the video contents of the two clips by manipulating the audio portions of the representations of the two media clips in the timeline  2600 . Also, the timeline  2600  allows the user to adjust the video transition independently from the audio transition. For instance, the timeline  2600  allows to move the video portion of the transition  2635  along the timeline  2600  independently from the audio portion of the transition  2635 . Furthermore, the timeline  2600  allows the user to adjust one or more types of media contents at the same time and without affecting the media clips&#39; other contents. 
     In the first stage  2605 , the timeline  2600  displays the media clips  2625  and  2630  along with another media clip before the media clip  2625 . The user has also placed a transition  2635  between the media clips  2625  and  2630 . 
     In the second stage  2610 , the timeline  2600  displays a menu bar  2640  that appears when the user clicks on the transition  2635 . The user selects an item that will result in displaying the audio portions of the two media clips separately from the video portions of the media clips. The timeline  2600  may provide numerous different ways of causing the timeline to display the audio portions separately. For instance, the timeline  2600  may provide hotkey commands that causes the timeline  2600  to display the audio portions separately. 
     In the third stage  2615 , the timeline  2600  displays the audio portion of the media clip  2625  further away from the video portion of the media clip  2625 . The timeline  2600  displays the audio portion of the media clip  2630  away from the video portion of the media clip  2630  and below the audio portion of the media clip  2625 . Parts of the audio portions span the same duration  2645  of the timeline  2600  to indicate that the audio content of the media clip  2625  is fading out over this duration and the audio content of the media clip  2630  is fading in over this duration. The diagonal lines that appear in the audio portion in some embodiments indicate that this fading effect currently applied to the audio contents of the two media clips are preset by the media-editing application. The media-editing application allows the user to select the video portion of the transition independently from the audio portions of the transition. For instance, the user can select (as indicated by the highlighted border of the video portion of the transition) and move to the left or to the right to adjust video transition. 
     In the fourth stage  2620 , the user has dragged the left edge of the audio portion of the media clip  2630  to the left in order to make the audio content of the media clip  2630  starts to fade in at an earlier point in time than before. The timeline  2600  in some embodiments may also allow the user to adjust video portions of the two media clips by manipulating the transition  2635 . For instance, the user can drag the transition  2635  to the left without affecting the audio portions of the two media clips in order to adjust the points in time at which the video contents of the two media clips start to fade in or finish fading out. 
     The media-editing application has removed the diagonal line for the audio portion of the media clip  2630 . This indicates the fade-in effect is not governed by the preset pattern represented by the diagonal line. The user will have to apply a fade-in effect as the user desires using fade handles similar to the fade handles  221  and  222  described above by reference to  FIG.  2   . 
     D. Moving Clips While Trimming 
       FIG.  27    illustrates expanding a space before the first media clip of a media presentation that is displayed in a timeline  2700  of a media-editing application. Specifically, this figure illustrates the timeline  2700  four different stages  2705 - 2720  to show that a space before a media clip  2725  expands as the in-point of a media clip  2725  is pulled in to trim the media clip  2725  from its beginning. The timeline  2700  is similar to the timeline  115  described above by reference to  FIG.  1   . 
     When a media clip in the timeline  2700  of some embodiments is trimmed from its beginning (i.e., when the media clip&#39;s in-point is pulled in), the media-editing application moves the media clips that come after the media clip being trimmed to the left while leaving the media clips that come before the media clip being trimmed static. This results in an impression to the user that the media clip that is being trimmed is trimmed from its ending. That is, this gives an impression that the out-point of the media clip that is being trimmed is pulled in. To prevent such impression from occurring, some embodiments of the media application moves the media clips that come before the media clip being trimmed from its beginning to the right. 
     The first stage  2705  shows the timeline  2700  before the user performs a trimming operation to the media clip  2730  in the timeline  2700 . The timeline  2700  displays the media clips  2725  and  2730  in the central compositing lane  2735 . The timeline  2700  also displays a rectangular space  2736  before the beginning of the sequence of the two media clips (i.e., before the media clip  2725 ). The second stage  2710  illustrates the selection of the left edge of the media clip  2730  in the timeline  2700 . The left edge of the media clip  2730  is the current in-point of this media clip  2730 . 
     The third stage  2715  illustrates the shortening of the media clip  2730  as the user of the media-editing application moves the right edge towards the center of the media clip. As the right edge of the media clip moves towards the center of the media clip  2730 , the media-editing application shortens the length of the media clip  2730  while leaving the right edge of the media clip  2730  static. Also, the media-editing application moves the media clip  2725  to the right and expands the space  2736  accordingly. In this manner, the media-editing application generates an impression that the media clip  2730  is trimmed from its beginning, not from its end. The fourth stage  2720  illustrates that, upon the performance of another operation, the media-editing application moves all media clips in the timeline  2730  to the left so as to contract the space  2736  to the length it originally had before the trimming operation initiated. In this example, the user has moved a scroll bar  2716  to the right. 
     V. Data Structures 
     In some embodiments, the media-editing application is an application that enables a user to create a composite media presentation from a set of media files. Through a graphical user interface (GUI) of the application, the user specifies the manner in which the media files are composited to create the composite presentation. In addition, through this GUI, the user can command the application to import one or more media files (e.g., from a camera, from an external drive, from an internal drive, etc.). Upon instructions from the user (i.e., through the media-editing application GUI) or as an automatic response to the detection of the media files in an external storage, the application copies the media files to a particular media storage location on a particular storage device. Some embodiments create a particular folder within the folder structure of the storage device for a set of imported media files (i.e., the media files imported at a particular time) and store a copy of the imported files in this particular folder at time of import. 
     When importing a media file, some embodiments create a media clip data structure for the imported media that links to the media file, any transcoded versions of the media file, and any analysis data about the media file. This media clip is the entity that is added to a media presentation in some embodiments in order to include the media file (or a portion of the media file) in the composite presentation. Some embodiments store this information in an asset data structure that specifically references the media and analysis files, and then additionally create a clip data structure that references the asset. In addition, the asset data structure may include metadata such as a UUID for the media file generated by the camera that captured the media, file format information, various video properties (e.g., frame rate, colorspace, pixel transform, dimensions, etc.), and various audio properties (e.g., channel count, track count, sample rate, etc.) of the media. 
     The references stored in the media clip (or asset) refer to the versions of the media file stored in the application&#39;s file storage. Some embodiments, for each set of imported media files, create separate folders for the original media and any type of transcoded media. In some embodiments, the transcoded media include both high-resolution and low-resolution encodes of the original media file that may be created on import or post-import. 
     In some embodiments, these references to the files are pointers to the locations of the files on the storage device. In some embodiments, the media-editing application initially sets the reference to the original media such that the data structure references the media file that is to be imported (e.g., the file on a camera) as the original media, then modifies this reference once the media file is copied to the application&#39;s file storage so that the data structure now references the media in the file storage. In some such embodiments, the application displays the media clips for the user to edit before the file is actually copied. This enables a user to begin creating a presentation using the media clip while the clip refers to a file stored on a camera, and then continue using the same clip once the file is copied with no interruption to the editing workflow. 
     Much like the folders for different versions of media files, some embodiments create separate folders within a folder for a set of imported files for each type of analysis file (e.g., a folder for person detection files, a folder for color balance files, a folder for shake detection files, etc.). In addition, some embodiments store additional clip data in the media clip, as opposed to a separate file. As one example, some embodiments store shake detection as a tag about the media file or a specific portion of the media file. 
       FIG.  28    conceptually illustrates a process  2800  of some embodiments for creating an asset data structure and a clip data structure referencing that asset. In some embodiments, process  2800  is performed as part of the import process of the media-editing application. The process  2800  will be described in part by reference to  FIGS.  29  and  31   .  FIG.  29    conceptually illustrates an asset data structure  2900  for a video asset, as well as an event data structure  2905  for an event that contains the video asset.  FIG.  31    conceptually illustrates a simplified clip data structure  3100  that contains a single asset. 
     As shown, the process begins by receiving (at  2805 ) a media file to import. The media file may be an audio file, a video file, or other type of media file. In the example shown in  FIG.  29   , the media file is a video file with audio channels (e.g., a “.mov” file). 
     Next, the process creates (at  2810 ) an asset data structure for the media file. At this point in the process, the asset data structure is an empty structure. Some embodiments define the data structure in a CoreData (SQLite) database file, an XML file (e.g., an XML file for an event), etc. As mentioned,  FIG.  29    illustrates an asset data structure  2900  for the media asset. The asset data structure  2900  is fully populated, and this data will be described further below. 
     In some embodiments, the asset data structure is created within an event data structure. If the event data structure does not yet exist, then the media-editing application also creates this data structure to contain the asset. As shown in  FIG.  29   , the asset data structure  2900  is one asset within the event data structure  2905 . The event data structure  2905  includes an event ID  2910 , the list of assets, and a list of clips. The event data structure may include additional fields in some embodiments, such as the event name, event date (which may be derived from asset information), etc. The event data structure  2905  may be a CoreData (SQLite) database file that includes the assets and clips as objects defined with the file, an XML file that includes the assets and clips as objects defined with the file, etc. 
     The process next retrieves (at  2815 ) metadata from the imported file, and then stores (at  2820 ) this metadata in the asset structure. The metadata is information about the source file and its stored media in some embodiments. In some embodiments, this metadata is used to generate the asset ID, described below. The asset data structure  2900 , as shown, includes source file metadata  2915 . As shown, the source file metadata includes the file type (e.g., audio, video, movie, still image, etc.), the file format (e.g., “.mov”, “.avi”, etc.), the source device (i.e., the device that created the media, such as the particular type of camera on which a movie file was captured), the file creation date (e.g., the date a video was captured, rather than the date of import), a UUID (a unique identifier generated by a media creation device such as a camera), set of video properties  2920 , a set of audio properties  2925 , and additional metadata. Different types (or manufacturers) of cameras create different UUIDs differently. These may be hashes of various data in some embodiments, such as a camera ID, record time (e.g., the time a user of the camera started recording, the duration of the video), etc., so long as no UUIDs will always be unique. 
     The video properties  2920  of some embodiments include such properties as a sample rate, a frame rate (i.e., the number of video images the video file contains per second, often 24, 25, or 30), the dimensions of the image (i.e., the number of pixels horizontally and number of rows of pixels), the pixel aspect ratio (i.e., the shape of the pixels, which may be square (HD video) or rectangular (e.g., NTSC video has a ratio of 10:11)), the pixel transform, and the colorspace in which pixel values of the image are defined (e.g., ITU-R BT.709 for HD, ITU-R BT.601 for SD, etc.). The audio properties  2925  of some embodiments include a sample rate (i.e., the number of audio samples per second, often 48 kHz), the number of audio tracks stored in the underlying media file, and the number of audio channels stored in the underlying media file. In some embodiments, the asset may additionally store override data that modifies one or more of the video or audio properties. For instance, a user might enter that a media file is actually 1080p, even though the file&#39;s metadata, stored in the asset, indicates that the video is 1080i. When presented to the user, or used within the application, the override will be used and the media file will be treated as 1080p. 
     Returning to  FIG.  28   , the process  2800  then creates (at  2825 ) an asset ID and stores the asset ID in the asset structure. The asset ID, in some embodiments, is a function of various properties of the underlying media file. For instance, some embodiments generate the asset ID as a hash of properties such as a file identifier, video properties, audio properties, and media range. The creation of the asset ID will be described in further detail by reference to  FIG.  30   . As shown in  FIG.  29   , the asset ID  2910  is stored in the video asset  2900 . 
     With the asset created, the process  2800  then begins populating the asset with references to various data. The process stores (at  2830 ) a reference to the original media file in the asset structure. As described above, this reference initially refers to the media file on the device from which the application is importing the file (e.g., the camera), and then once the file is copied to the application&#39;s folder structure, the reference is modified to refer to the copied media file. 
     Next, the process  2800  creates (at  2835 )) a clip data structure containing a reference to the asset, in some embodiments, a clip is created for each asset. As will be described below, clip data structures (e.g., clip objects) can also contain other clips, and some embodiments use the same data structure for single asset clips, compound clips containing multiple assets and/or nested clips, and project sequences. The clip data structure, like the asset, is contained in the event data structure in some embodiments. Some embodiments create a series of nested clip objects for an imported clip, as described in further detail below. The lowest clip object in the nested hierarchy references the asset. 
     Next, the process determines (at  2840 ) whether any transcoded versions of the media are generated by the media-editing application. As described in subsections A and B above, some embodiments generate one or more transcoded versions of imported media files in formats that are better suited for editing. This may be an automatic process based on the imported file properties, or based on user selection of whether to transcode the media. When one or more transcoded versions of the media are created, the process stores (at  2845 ) references to any such transcoded versions of the media file in the asset data structure. 
     The process also determines (at  2850 ) whether any analysis data is generated for the media by the media-editing application. As described above, some embodiments generate data about the video and/or audio data of a media file. This data may be generated automatically or based on user selection of particular analysis operations. When one or more analysis data files are created, the process stores (at  2855 ) references to any such analysis data files in the asset data structures. The process  2800  then ends. 
     The media asset  2900  of  FIG.  29    includes references to three versions of the underlying media file: a copy of the original media file  2930 , a high resolution transcoded media file  2935 , and a low resolution transcoded media file  2940 . In addition, the media asset includes references to a person detection file  2945 , a color correction data file  2950 , and a shake correction data file  2955 . These data files are described in further detail in the subsections above. In some embodiments, the references stored in the asset data structures are pointers to the locations of the video on a physical storage device (e.g., the boot disk of the device on which the media-editing application operates). In the case of media asset  2900 , the underlying file stores both audio and video. In some media formats, different files are used to store video and audio for a single shot (and there may be multiple audio files recorded by different audio recorders in some cases). In this case, some embodiments create separate assets for each file. In some embodiments, each media file gets its own asset data structure. 
     As mentioned in the discussion of  FIG.  29   , the asset ID for a particular asset may be generated using various properties of the asset&#39;s underlying media file.  FIG.  30    conceptually illustrates a process  3000  of some embodiments for generating the asset ID and storing the ID in the data structure. In some embodiments, process  3000  is performed at operation  2825  of process  2800 . 
     As shown, the process  3000  begins (at  3005 ) by receiving a media file (e.g., a video file, audio file, movie file, etc.). The process then identifies (at  3010 ) the media file ID, video properties, audio properties, and media range of the media file. As shown in  FIG.  29   , these may be stored as metadata of the source media file. The media file ID, in some embodiments, is a UUID generated by a camera that shot the media file, as described above. In some cases, the file may not have a UUID (e.g., if the device that captured the file does not generate UUIDs), and some embodiments will instead use the file name. The video properties used in some embodiments are the dimensions, colorspace, field dominance, sample duration, frame duration, pixel transform, and pixel aspect ratio, though different video properties may be used in different embodiments. The sample duration may be different from frame duration if, for example, the video is field rendered, in which case the frame duration is twice the sample duration. The frame duration, in some embodiments, is the inverse of the frame rate (e.g., if the frame rate is 30 fps, then the frame duration is 1/30 of a second). The audio properties used in some embodiments are the number of tracks, number of channels, and sample rate (i.e., the same as shown in audio properties  2925 ). Some embodiments include additional properties, such as the file creation date (i.e., the date and/or time at which the media was captured (e.g., filmed, photographed, recorded, etc.)). 
     The media range indicates the range of the original media file reference by the particular asset. Some embodiments use timecode values of the media file to define the media range. Thus, if a file is split apart (e.g., a user might take a thirty minute video and split it into a twelve minute video, a seven minute video, and an eleven minute video, as well as retain the original), the different timecodes will differentiate the assets. The media range can also be used if one of the assets goes missing, as an asset with identical properties and a range including the media range of the missing assets can be used to restore the missing asset. 
     The process then generates (at  3015 ) a hash of the identified properties of the media file. Different embodiments use different hash algorithms (e.g., MD5, etc.). The process then stores (at  3020 ) this generated hash in the asset structure as the asset ID. While the process  3000  describes one method of computing an asset II), one of ordinary skill will recognize that asset IDs can be computed using many different properties and many different computation algorithms. 
     As mentioned above, some embodiments use a clip structure that references one or more assets when importing a media file.  FIG.  31    illustrates a component clip data structure  3100  of some embodiments that references an asset. In some embodiments, the component clip  3100  is the lowest level of a set of nested clip objects, that are all members of the same class. The details of clip objects of some embodiments will be described below by reference to  FIG.  32   . 
     The component clip  3100  includes a clip ID, clip attributes (described in more detail below), and an asset reference  3105 . The asset reference  3105  of some embodiments stores an event ID and an asset ID, and uniquely identifies a particular asset data structure, as indicated by the dashed arrow referring to an asset. The arrow is shown as dashed because the asset reference is not a direct reference to the asset, but rather is used to locate the asset when needed. When the media-editing application of some embodiments needs to identify a particular asset, the application uses the event ID to locate the event that contains the asset, and then the asset ID to locate the particular desired asset. 
       FIG.  32    conceptually illustrates a nested sequence of clip objects created by the media-editing application of some embodiments for an imported media file. In some embodiments, each of the clip objects shown in this figure is a member of the same class, though the object may be of different sub-classes. The media file whose clip structure is illustrated in  FIG.  32    is a movie file that stores both audio and video information. 
     The figure illustrates a sequence  3205 , a collection  3210 , and two components  3215  and  3220 . As mentioned, these three types of objects are all subclasses of clip objects (or anchored objects) in some embodiments. Some embodiments create a sequence within an event object for each imported media clip. The sequence  3205  stores a sequence ID, a set of sequence attributes, and the collection object  3210 . The sequence ID is a unique identifier for the sequence object. The sequence attributes, in some embodiments, include video properties for the sequence, such as the resolution, frame rate, etc. The attributes may be set by a user in some embodiments, or set automatically based on the underlying media. 
     The collection object  3210  is an ordered array of clip objects. In the case of a clip imported into an event, as is the case with object  3210 , the collection stores one or more component clips in the array. Often, the collection only stores the video component clip in the array, as shown here; any additional components (generally one or more audio components) are then anchored to that video component. In addition, the collection object  3210  stores a collection ID, a total range, and a trimmed range. The collection ID is a unique identifier for the collection object. The total range of a clip object indicates the maximum range for the object based on the objects it contains, while the trimmed range indicates the actual range of the object in its parent object according to user edits. In some embodiments, the collection object stores a value for the total range because the total range is a variable assigned to all types of clip objects, but this range is not actually used by the application. Instead, the application dynamically calculates the total range based on the objects contained by the collection (as opposed to updating the range value every time a clip is added to the collection). Some embodiments, on the other hand, do update the total range in the collection object. These ranges will be described in further detail below by reference to  FIG.  33   . The array of the collection object includes two media components  3215  and  3220 . Collection objects, in some embodiments, can include component clip objects as well additional collections. 
     In the above paragraph and elsewhere in this section, a first object (e.g., the collection object  3210 ) is described as containing a second object (e.g., media component  32  in the collection object&#39;s array). In some embodiments, a first object contains a second object by storing a reference to the object (e.g., a pointer). This reference is a strong pointer in some embodiments. 
     The media components shown include a video component  3215  and an audio component  3220 . These are the same data structures as the component clip  3100 , in some embodiments, and thus store the clip attributes and the asset reference shown in that figure. Each of the components stores a component ID (i.e., the clip ID of  FIG.  31   ), a source media range (i.e., total range) and a trimmed range. For a component clip that refers to a media asset, the total range is the duration of the source media. The trimmed range is the range selected by a user through various user edits (e.g., trim edits) and indicates both the start time within the total range and the duration, in some embodiments. The trimmed range is generally a subset of the total range (i.e., does include time outside the total range). However, in some embodiments, the application may use a range extender to extend the trimmed range past the total range (e.g., when needed for part of a transition, or if aligned audio runs slightly longer than video). Some embodiments will generate video images using, e.g., the first and last images of the video file, to fill in the needed extra range. When a clip is initially imported into the application, the total range and trimmed range will generally be equal as the user will not have edited the clip at all yet. 
     The video component  3215  includes an anchored item set that contains the audio component  3220 . As described above by reference to the timeline  115  in the user interface  100  of  FIG.  1   , clips can be anchored to other clips in some embodiments. When a particular clip is moved in a timeline, any clips anchored to the particular clip are moved along with it. Each clip can have numerous clips anchored to it, and can be anchored to a single clip. In the case of a media clip with audio and video components, some embodiments anchor the audio component to the video component. Thus the video component object  3215  contains the audio component in its set of anchored items (and could include numerous such items if there were additional audio components), while the audio component object  3220  includes a parent item reference to the video component to which it is anchored. In addition, the child (anchored) object stores an anchor offset that indicates two values. The first value is the position in the parent object to which the child object is anchored, and the second value is the offset within the child object of the anchor. In the case of an imported media file, the audio and video components will start at the same time, and thus both anchor offset values are zero. However, this can be modified if, for example, there is a slight offset in the recordings of the two components and the user has to adjust the audio relative to the video. 
       FIG.  33    conceptually illustrates the objects  3205 - 3220  nested in a conceptual timeline. The figure shows video and audio components  3215  and  3220  inside the collection  3210 , which is nested inside the sequence  3205 . The audio component  3220  is anchored to the video component  3215 ; specifically, as shown by the thick arrow  3305 , the start of the audio component is anchored to the start of the video component. 
     The figure also includes a dashed box  3310  that illustrates that a user has trimmed the clips so that portions at the beginning and end of the clip are not part of the sequence were it to be rendered. Thus, the total media range of the components is the full length of the media to which they refer, whereas the trimmed range is a subset of this range based on the user edits. In some embodiments, all clip objects store a total range and trimmed range. The collection  3210 , in this case, will have the same total range and trimmed range as the components. However, if the components were offset, or if the collection included additional objects, it would have larger trimmed and total ranges. For sequence objects, the total range and trimmed ranges are always equal in some embodiments. In the illustrated case, the sequence  3205  has a range equal to the trimmed range of the collection  3210 . As the user edits the objects in the sequence, both the trimmed and total ranges of the sequence change. In some embodiments, these ranges are based on units of time, number of frames, and/or number of audio samples. As described above by reference to  FIG.  2   , the media-editing application of some embodiments provides a volume control for a user of the application to control the volume of a media clip displayed in the timeline. 
       FIG.  34    illustrates a timeline  3400  with a project title “New Project” that includes four clips  3405 - 3420 . The clips  3405 - 3415  are in the primary compositing lane of the project&#39;s sequence, while the clip  3420  is anchored to clip  3410  at approximately 26 seconds into clip  3410 . The clip  3410  is a compound clip that itself includes two clips. 
       FIG.  35    conceptually illustrates a subset of the data structures for the sequence illustrated in  FIG.  34   . In some embodiments, the data structures of  FIG.  35    are all contained within a project data structure that contains a single sequence. In some embodiments, the project data structure for a project in the timeline is a sub-class of a class that also includes event data structures. Unlike the project data structures, the event data structures can contain multiple sequences, and in fact contain a sequence (such as sequence  3305 ) for each clip in the event. 
       FIG.  35    illustrates a sequence  3500  that includes a primary collection data structure  3503 , which itself is an array of three collections  3505 - 3515  that correspond to the clips  3405 - 3415 . In addition, the fourth clip  3420  is stored as a data structure within the collection  3510 . For simplicity, the component objects are not shown in this figure. The sequence  3500  includes a sequence ID, sequence attributes, and the primary collection  3503 . The sequence attributes for a project in the timeline are set by a user when creating the project, in some embodiments. 
     The primary collection  3503  includes the collection ID, total and trimmed range, and the array of media clips. In some embodiments, the array is ordered based on the location in the timeline and only includes media clips in the primary lane of the collection. The application assumes that there is no gap between these items, and thus no timing data is needed between the items. As shown, each of these clips is represented as a collection. When a clip stored in an event (e.g., the clip shown in  FIG.  32   ) is added to a project in a timeline, some embodiments remove the sequence container data structure (e.g., structure  3205 ) and copy the rest of the structure (i.e., the collection and its components) into the data structure for the object in the timeline. 
     Clips  3505 ,  3515 , and  3520  are individual clips that have been added to the timeline from the clip browser, and thus do not themselves include collections. Similar to the collection  3210 , these objects include an ID, total and trimmed ranges, and an array of media components (e.g., a video component and one or more audio components). 
     The clip  3510  is a compound clip and therefore includes multiple clips in addition to the collection ID and ranges. Specifically, the clip  3510  includes two media clips  3525  and  3530 . Within the collection, the clips are both in the primary lane of the collection, and thus one follows the next. These clip objects are not shown in this figure, but each of the clips is similar to clip  3505  in that the clips include an array of media components. In addition, the clip object  3510  includes a set of anchored items (in this case only the one item, clip  3520 ). Some embodiments include a set of anchored items for each collection, which are empty for the other objects shown in this figure. The anchor offset stored in clip  3520  indicates that it is anchored 26 seconds into clip  2 , and that the anchor is at the start of clip  3520 . These times refer to the trimmed ranges of the clips in some embodiments. 
     When one of clips  3405 ,  3510 , and  3515  is removed from the spine and placed in the anchor lane above the spine like clip  935  does as illustrated in  FIG.  9    above, the corresponding entry in the media component array of the primary collection  3503  will be removed from the array and the primary collection will include an anchored item that associates with the collection for the removed clip. The collection for the removed clip will then include anchored offsets. Conversely, when anchored clip  3420  is inserted into the spine as the second media component of the primary collection  3503  like clip  1025  does as illustrated in  FIG.  10    above, the primary collection will create an entry for the collection #9220 in the array of the media components. The anchored offsets will be deleted from the collection  3520 . Also, the anchored item for the collection  3520  in the collection  3510  will be deleted. When the anchored clip  3420  is moving along the timeline as clip  1130  does as illustrated in  FIG.  11    above, the first value of the anchor offsets in the collection  3520  will be modified accordingly. 
       FIG.  36    conceptually illustrates the objects  3500 - 3230  nested in a conceptual timeline. As shown, collection objects  3525  and  3530  are nested inside the collection  3510 , which is nested inside the primary collection object  3503  along with the collection objects  3505 ,  3515 , and  3520 . The collection object  3503  is itself nested inside a sequence object. 
     The figure illustrates the anchoring relationships between the various clips as well as the durations (ranges) of the clips. As with the clip objects shown in  FIG.  33   , each of the lowest level collections  3505 ,  3515 ,  3525 , and  3530  each have an audio component anchored to a video component. While not shown, collection  3520  could also have the same video/audio setup, or could be just a video component (or just an audio component). While each of the objects shown has a single audio component, one of ordinary skill will recognize that some embodiments will have multiple audio components (e.g., if a camera records several audio tracks as separate files and imports the files with a video file as part of a single clip). 
     The figure also illustrates the anchoring of clip  3520  to clip  3510 . In some cases, multiple clips will be anchored to the same primary lane clip, and the multiple anchored clips may overlap in time. In this case, multiple secondary lanes may be used. Some embodiments assign lane numbers to each clip object that indicates the clip object&#39;s lane within a collection. 
     All of the primary lane objects are assigned a lane number of zero in some embodiments, with lanes above the primary lane getting increasing numbers and lanes below the primary lane getting decreasing (negative) numbers. For instance, a separate audio clip might be anchored to a clip in the primary lane and displayed below the primary lane. In this case, within the primary collection  3503 , the anchored clip  3520  has a lane number of 1. The lane numbers indicate compositing order for video in some embodiments. Whereas two audio files can be combined fairly easily (mixed), two video files cannot be displayed at the same time. Thus, some embodiments composite higher lane number clips on top of lower lane number clips. If no compositing effect is defined between two clips at the same time, then the clip in the higher lane will be displayed. However, various compositing modes and effects may be used to combine the pictures (e.g., compositing modes such as subtract, darken, multiply, etc. that combine pixel information of two images, as well as effects such as scaling the top image to get a picture-in-picture, applying a color mask to the top image, etc.). 
     The items in a lower-level nested collection will also have lane numbers that refer to their lane order within that collection. For example, the collection object  3510  has two clips  3525  and  3530 , that each have a lane number of zero. However, this collection object could have anchored clips in multiple lanes. For the purpose of compositing at time of rendering, the items within the collection  3510  would be composited initially according to the ordering within the collection, then the output of that would be composited within the primary collection according to the ordering of the primary collection. Similarly, for each of the lowest-level collections (e.g., collection  3505 ), the video components are all lane zero and the audio components are lane −1. 
       FIG.  36    also illustrates the ranges (e.g., durations) of the various clip objects. For the lowest level collections and their components (e.g., collections  3505 ,  3515 ,  3525 ,  3530 , and  3520 ), the trimmed range and the total range are determined in a manner similar to that shown in  FIG.  33    for the collection object  3210 . In this case, collections  3515  and  3555  are not trimmed at all, whereas collection  3505  is trimmed on both sides and the start of collection  3530  is trimmed. 
     For collection  3510 , the total range is the sum of the trimmed ranges of its primary lane clips, which in this case are collections  3525  and  3530 . Thus, the variable Total Range 2=Trimmed Range A+Trimmed Range B. In this case, the collection  3510  is not separately trimmed, such that its trimmed range equals its total range. This means that, although there is more media within clip  3530 , while editing the primary collection  3503  the media-editing application will not allow a user to increase the duration of clip  3510  beyond that of Total Range 2. However, a user could open up the clip  3510  in the timeline and apply trim edits to either of clip  3525  and  3530 . Modifications to the trimmed range of these clips will affect the total range of the clip  3510 . In addition, within the primary collection  3503 , a user can modify the trimmed range of clip  3510  to shorten the clip. Trimming from the beginning would result in less of the media of collection  3525  being used in the component presentation, while trimming from the end would result in less of the media of collection  3530  being used in the composite presentation. 
     The above figures illustrated various aspects of different subclasses of clip objects (e.g., sequences, collections, and components). One of ordinary skill will recognize that clip objects of some embodiments may have additional properties not shown in these figures. For instance, both collections and components may have an effect stack in some embodiments, which stores a stack of effects that are applied to the media in the clip when the application renders the clip. The application applies these affects to the media in an order designated by the effects stack, which can be modified by the user during editing. The effects may include audio effects that perform a transform on the audio or video effects that apply a function to the pixel values of the video images, in some embodiments. In fact, some embodiments store separate video and audio effects stacks. 
     In addition, one of ordinary skill in the art will recognize that some embodiments may have additional different subclasses of clip objects. For instance, some embodiments store generators, transitions, audition stacks, markers, and keywords as clip objects. A generator, in some embodiments, is an effect used in a composite presentation that creates its own video images rather than modifying existing images (e.g., clouds and other computer-generated effects that may rely on random processes). Some embodiments also use generators as gap elements (e.g., a position clip) in collections in specific circumstances. If, for example, a user were to select clip objects  3505  and  3520  and create a compound clip from these objects, a gap element would be inserted into the collection object for the compound clip to take up the missing space of clip object  3510 , which the user did not add to the collection. The clip object  3520  would then be anchored to this gap element. In some embodiments, these clips are not actually generators, but are special clips that produce neither audio nor video but add duration to a collection. As the generators create their own video images, they have a duration and this duration adds to the range of the collection containing the generator. 
     Transition objects, on the other hand, are used for transitions between two other clip objects. These objects have a range of 0, and do not add to the range of the container clip object. A transition object is stored in the array of its containing collection with an index between the indices of the two items between which it transitions. The transition object has a head and a tail that indicate the start and end of the transition between the clips. 
     Audition stack objects, or variants, store a list of possible clips for a particular index in a collection or for a particular anchor. That is, the audition stack object stores a set of clips, one of which is designated as active at any time. The properties of the stack object take on the properties of the active clip, such as the ranges, video properties e.g., frame rate, resolution, etc.), audio properties, etc. Thus, when a user switches the active clip in the stack, some attributes of the stack may change. In addition, some of the objects in the stack may be collections that themselves have nested clips, while others might be simpler clip objects. When an audition stack object is anchored to another clip, some embodiments store the first portion of the anchor offset in the audition object (i.e., the offset within the parent clip), but store different offsets within the child clip for the different clips in the audition. 
     Marker objects store markers that a user adds to a specific time location in a collection. In some embodiments, marker objects have a duration of 1 frame, and store metadata indicating the type of marker (e.g., to do marker, analysis marker, etc.) and any notes about the marker that the user adds. Some embodiments anchor marker objects to a particular clip object. When calculating the duration of a collection, marker objects are specifically excluded from this calculation in some embodiments. 
     Finally, keyword objects store keyword tags about a clip object. Unlike markers, keywords have a range, as some embodiments provide the user the ability to tag a particular range of a clip rather than just associating the keyword with the entire clip. In some embodiments, a keyword object can store multiple keywords that have the same range. Some embodiments anchor keyword objects to the tagged clip object at the start of the range within the tagged object. Like markers, some embodiments specifically exclude keyword objects from the duration calculation for a collection. 
       FIG.  37    conceptually illustrates a state diagram  3700  for a media-editing application of some embodiments. Specifically, state diagram  3700  refers to the creation and modification of clip data due to various user actions. As shown, when the application is not receiving any such actions, the application is in the wait state  3705 . 
     When a user imports a file, the application transitions to  3710  to create a clip object in an event for the imported file. The event may also need to be created, depending on whether the user is importing the file to an existing event. The clip object, as shown above, refers to an asset that refers to the file. The application then returns to the wait state  3705 . 
     When the user adds a clip to the timeline (e.g., by dragging the clip from the browser to the timeline), the application transitions to  3715  and duplicates the clip object from the event to create a new clip object that is part of the project currently edited in the timeline. The clip data is partly the same (i.e., the same asset reference), but may also refer to only a portion of the asset (i.e., may have in and out points). In addition, the application transitions to  3720  to add information for the new clip object to the timeline clip object attributes. That is, the timeline is also represented by a clip object in some embodiments (e.g., may be a project, compound clip, etc.) and this data structure will be modified to refer to the new clip and store the position of the new clip. The application then returns to the wait state  3705 . 
     When the user duplicates a clip in the timeline (as opposed to adding a clip from the browser), the application transitions to  3725  to duplicate the clip object from the clip in the timeline. This is a similar process as described above at state  3715 . In addition, the information about the new clip is added to the timeline clip object at state  3730 . Furthermore, at both state  3730  and state  3720 , clip information in the timeline clip object may need to be modified to account for movement of other clips. 
     When the user edits a clip in the timeline (e.g., moves the clip), the application transitions to  3735  to modify the information for the edited clip object in the timeline clip object attributes this may involve modifying its horizontal (time) and/or hierarchical position if the clip is moved. In addition, if the clip is trimmed, the information in the edited clip may need to be changed (i.e., its in and out points in the source media). 
     VI. Software Architecture 
     In some embodiments, the processes described above are implemented as software running on a particular machine, such as a computer or a handheld device, or stored in a machine readable medium.  FIG.  38    conceptually illustrates the software architecture of a media editing application  3800  of some embodiments. In some embodiments, the media editing application is a stand-alone application or is integrated into another application, while in other embodiments the application might be implemented within an operating system. Furthermore, in some embodiments, the application is provided as part of a server-based solution. In some such embodiments, the application is provided via a thin client. That is, the application runs on a server while a user interacts with the application via a separate machine remote from the server. In other such embodiments, the application is provided via a thick client. That is, the application is distributed from the server to the client machine and runs on the client machine. 
     The media editing application  3800  includes a user interface (UI) interaction and generation module  3805 , a media ingest module  3810 , editing modules  3815 , rendering engine  3820 , playback module  3825 , timeline features module  3895 , playhead control module  3830 , multi-track editor  3835 , and precision editor  3845 . 
     The figure also illustrates stored data associated with the media-editing application: source files  3850 , events data  3855 , project data  3860 , layout data  3890 , and render files  3865 . In some embodiments, the source files  3850  store media files (e.g., video files, audio files, combined video and audio files, etc.) imported into the application. The source files  3850  of some embodiments also store transcoded versions of the imported files as well as analysis data (e.g., people detection data, shake detection data, color balance data, etc.). The events data  3855  stores the events information used by some embodiments to populate the clip library and clip browser. The events data may be a set of clip object data structures stored as one or more SQLite database files (or other format) in some embodiments. The project data  3860  stores the project information used by some embodiments to specify a composite presentation in the timeline. The project data may also be a set of clip object data structures stored as one or more SQLite database files (or other format) in some embodiments. The layout data  3890  stores layout information (e.g., coordinates, length, width, lane numbers, etc.) of all clips that are displayed in the timeline. In some embodiments, the layout data  3890  is part of the project data  3860 . The render files  3865  of some embodiments may include thumbnail-sized images for display in the clip browser or timeline, audio waveform displays for media clips, as well as rendered segments of a timeline sequence for use in playback. In some embodiments, the four sets of data  3850 - 3865  are stored in one physical storage (e.g., an internal hard drive, external hard drive, etc.). In some embodiments, the data may be split between multiple physical storages. For instance, the source files might be stored on an external hard drive with the events data, project data, and render files on an internal drive. Some embodiments store events data with their associated source files and render files in one set of folders, and the project data with associated render files in a separate set of folders. 
       FIG.  38    also illustrates an operating system  3870  that includes input device driver(s)  3875 , display module  3880 , and media import module  3885 . In some embodiments, as illustrated, the device drivers  38875 , display module  3880 , and media import module  3885  are part of the operating system even when the media editing application  3800  is an application separate from the operating system. 
     The input device drivers  3875  may include drivers for translating signals from a keyboard, mouse, touchpad, tablet, touchscreen, etc. A user interacts with one or more of these input device, which send signals to their corresponding device driver. The device driver then translates the signals into user input data that is provided to the UI interaction and generation module  4305 . 
     The present application describes a graphical user interface that provides users with numerous ways to perform different sets of operations and functionalities. In some embodiments, these operations and functionalities are performed based on different commands that are received from users through different input devices (e.g., keyboard, trackpad, touchpad, mouse, etc.). For example, the present application illustrates the use of a cursor in the graphical user interface to control (e.g., select, move) objects in the graphical user interface. However, in some embodiments, objects in the graphical user interface can also be controlled or manipulated through other controls, such as touch control. In some embodiments, touch control is implemented through an input device that can detect the presence and location of touch on a display of the device. An example of such a device is a touch screen device. In some embodiments, with touch control, a user can directly manipulate objects by interacting with the graphical user interface that is displayed on the display of the touch screen device. For instance, a user can select a particular object in the graphical user interface by simply touching that particular object on the display of the touch screen device. As such, when touch control is utilized, a cursor may not even be provided for enabling selection of an object of a graphical user interface in some embodiments. However, when a cursor is provided in a graphical user interface, touch control can be used to control the cursor in some embodiments. 
     The display module  3880  translates the output of a user interface for a display device. That is, the display module  3880  receives signals (e.g., from the UI interaction and generation module  3805 ) describing what should be displayed and translates these signals into pixel information that is sent to the display device. The display device may be an LCD, plasma screen, CRT monitor, touchscreen, etc. 
     The media import module  3885  receives media files (e.g., audio files, video files, etc) from storage devices (e.g., external drives, recording devices, etc.) through one or more ports (e.g., a USB port, Firewire port, etc.) of the device on which the application  3800  operates and translates this media data for the media-editing application or stores the data directly onto a storage of the device. 
     The UI interaction and generation module  3805  of the media editing application  3800  interprets the user input data received from the input device drivers and passes it to various modules, including the media ingest module  3810 , the editing modules  3815 , the rendering engine  3820 , the playback module  3825 , the timeline features module  3895 , the playhead control module  3830 , the multi-track editor  3835 , the precision editor  3845 , and the timeline layout managers  3840 . The UI interaction module also manages the display of the UI, and outputs this display information to the display module  3880 . This UI display information may be based on information from the editing modules  3825 , the playback module  3825 , the timeline features module  3895 , the playhead control module  3830 , the multi-track editor  3835 , the precision editor  3845 , and the data  3850 ,  3855 ,  3860 ,  3890 , and  3865 . 
     The media ingest module  3810  manages the import of source media into the media-editing application  3800 . Some embodiments, as shown, receive source media from the media import module  3885  of the operating system  3870 . The media ingest module  3810  receives instructions through the UI module  3805  as to which files should be imported, then instructs the media import module  3885  to enable this import (e.g., from an external drive, from a camera, etc.). The media ingest module  3810  stores these source files  3850  in specific file folders associated with the application. In some embodiments, the media ingest module  3810  also manages the creation of event data structures upon import of source files and the creation of the clip and asset data structures contained in the events. 
     The editing modules  3815  include a variety of modules for editing media in the clip browser as well as in the timeline. The editing modules  3815  handle the creation of projects, addition and subtraction of clips from projects, trimming or other editing processes within the timeline (e.g., inserting, deleting, anchoring, appending, etc.), application of effects and transitions, or other editing processes. In some embodiments, the editing modules  3815  create and modify project and clip data structures in both the event data  3855  and the project data  3860 . Moreover, the editing modules  3815  works with the timeline layout managers  3840  to manage the layouts of the clips and effects (e.g., transitions) displayed in the timeline. 
     The rendering engine  3820  handles the rendering of images for the media-editing application. In some embodiments, the rendering engine manages the creation of images for the media-editing application. When an image is requested by a destination within the application (e.g., the playback module  3825 ) the rendering engine outputs the requested image according to the project or event data. The rendering engine retrieves the project data or event data that identifies how to create the requested image and generates a render graph that is a series of nodes indicating either images to retrieve from the source files or operations to perform on the source files. In some embodiments, the rendering engine schedules the retrieval of the necessary images through disk read operations and the decoding of those images. 
     The playback module  3825  handles the playback of images (e.g., in a preview display area of the user interface. Some embodiments do not include a playback module and the rendering engine directly outputs its images to the UI module  3810  for integration into the GUI, or directly to the display module  3880  for display at a particular portion of the display device. 
     In some embodiments, the render engine performs various operations to generate an output image. In some embodiments, these operations include blend operations, effects (e.g., blur or other pixel value modification operations), color space conversions, resolution transforms, etc. In some embodiments, one or more of these processing operations are actually part of the operating system and are performed by a GPU or CPU of the device on which the application  3800  operates. The output of the rendering engine (a rendered image) may be stored as render files in storage  3865  or sent to a destination for additional processing or output (e.g., playback). 
     The timeline layout managers  3840  manage the layouts of the clips and effects (e.g., transitions) displayed in the timeline. For instance, the layout managers  3840  update the layout data  3865  as media clips in the timeline changes (e.g., by being edited, moved, deleted, etc.). The timeline layout managers  3840  interact with the editing modules  3815  to receive editing operations performed on the items displayed in the timeline. The timeline layout managers  3840  also interact with the numerical editor  3845  as well to get any editing updates. In some embodiments, each timeline layout manager has a one-to-one relationship with the spine in managing the layouts of the clips that are in the spine or anchored to the clips in the spine. As described above, the timeline layout managers  3840  may work with the editing modules  3815  in managing the layouts of the clips displayed in the timeline. Moreover, the layout managers  3815  in some embodiments perform the processes  1700  and  1900  described above by reference to  FIGS.  17  and  19   . 
     The timeline features module  3895  handles various features of the timeline in some embodiments provide. For instance, the timeline features module  3895  manages the separation of audio and video portion of a media clip displayed in the timeline. The timeline features module  3895  also controls the volume of a media clip that has audio content. These timeline features are described above by reference to  FIG.  2   . The timeline features module  3895  also communicates with the timeline layout managers  3840  and the editing modules  3815  for handling any changes in the layouts of the clips in the timeline and editing operations performed by using the provided timeline features. 
     The playhead control module  3830  manages playheads in the timeline in some embodiments. The playhead control module  3830  communicates with the editing modules  3815  to manage editing operations that are performed by using playheads. For instance, the playhead control module  3830  works with the editing modules  3815  for anchoring media clips based on the position of the primary playhead in the timeline. The playheads of some embodiments are described above by reference to  FIG.  2   . 
     The multi-track editor  3835  is a multi-track editing tool of some embodiments described above by reference to  FIG.  22   . As described above, the multi-track editor opens a media clip within the timeline for editing in multi-tracks. This multi-track editor opens different tracks contained in a media clip in different lanes to allow the user to edit individual tracks of the media clip independently. In some embodiments, the multi-track editor  3835  communicates with the timeline layout manager  3840  and the editing modules  3815  when performing edit operations on the opened media clip. 
     The precision editor  3845  is a precision editing tool of some embodiments described above by reference to  FIG.  23   . As described above, the precision editor splits the spine into two lanes and places each of two media clips to which a transition is applied in one of the two lanes for editing. In some embodiments, the precision editor  3835  communicates with the timeline layout manager  3840  and the editing modules  3815  when performing edit operations on the two media clips. 
     While many of the features of media-editing application  3800  have been described as being performed by one module (e.g., the UI interaction and generation module  3805 , the media ingest manager  3810 , etc.), one of ordinary skill in the art will recognize that the functions described herein might be split up into multiple modules. Similarly, functions described as being performed by multiple different modules might be performed by a single module in some embodiments (e.g., the playback module  3825  might be part of the UI interaction and generation module  3805 ). 
     VII. Electronic System 
     Many of the above-described features and applications are implemented as software processes that are specified as a set of instructions recorded on a computer readable storage medium (also referred to as computer readable medium). When these instructions are executed by one or more computational or processing unit(s) (e.g., one or more processors, cores of processors, or other processing units), they cause the processing unit(s) to perform the actions indicated in the instructions. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, random access memory (RAM) chips, hard drives, erasable programmable read only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), etc. The computer readable media does not include carrier waves and electronic signals passing wirelessly or over wired connections. 
     In this specification, the term “software” is meant to include firmware residing in read-only memory or applications stored in magnetic storage which can be read into memory for processing by a processor. Also, in some embodiments, multiple software inventions can be implemented as sub-parts of a larger program while remaining distinct software inventions. In some embodiments, multiple software inventions can also be implemented as separate programs. Finally, any combination of separate programs that together implement a software invention described here is within the scope of the invention. In some embodiments, the software programs, when installed to operate on one or more electronic systems, define one or more specific machine implementations that execute and perform the operations of the software programs. 
       FIG.  39    conceptually illustrates an electronic system  3900  with which some embodiments of the invention are implemented. The electronic system  3900  may be a computer (e.g., a desktop computer, personal computer, tablet computer, etc.), phone, PDA, or any other sort of electronic device. Such an electronic system includes various types of computer readable media and interfaces for various other types of computer readable media. Electronic system  3900  includes a bus  3905 , processing unit(s)  3910 , a graphics processing unit (GPU)  3915 , a system memory  3920 , a network  3925 , a read-only memory  3930 , a permanent storage device  3935 , input devices  3940 , and output devices  3945 .
     The bus  3905  collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the electronic system  3900 . For instance, the bus  3905  communicatively connects the processing unit(s)  3910  with the read-only memory  3930 , the GPU  3915 , the system memory  3920 , and the permanent storage device  3935 .   

     From these various memory units, the processing unit(s)  3910  retrieves instructions to execute and data to process in order to execute the processes of the invention. The processing unit(s) may be a single processor or a multi-core processor in different embodiments. Some instructions are passed to and executed by the GPU  3915 . The GPU  3915  can offload various computations or complement the image processing provided by the processing unit(s)  3910 . In some embodiments, such functionality can be provided using CoreImage&#39;s kernel shading language. 
     The read-only-memory (ROM)  3930  stores static data and instructions that are needed by the processing unit(s)  3910  and other modules of the electronic system. The permanent storage device  3935 , on the other hand, is a read-and-write memory device. This device is a non-volatile memory unit that stores instructions and data even when the electronic system  3900  is off. Some embodiments of the invention use a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) as the permanent storage device  3935 . 
     Other embodiments use a removable storage device (such as a floppy disk, flash memory device, etc., and its corresponding disk drive) as the permanent storage device. Like the permanent storage device  3935 , the system memory  3920  is a read-and-write memory device. However, unlike storage device  3935 , the system memory  3920  is a volatile read-and-write memory, such as random access memory. The system memory  3920  stores some of the instructions and data that the processor needs at runtime. In some embodiments, the invention&#39;s processes are stored in the system memory  3920 , the permanent storage device  3935 , and/or the read-only memory  3930 . For example, the various memory units include instructions for processing multimedia clips in accordance with some embodiments. From these various memory units, the processing unit(s)  3910  retrieves instructions to execute and data to process in order to execute the processes of some embodiments. 
     The bus  3905  also connects to the input and output devices  3940  and  3945 . The input devices  3940  enable the user to communicate information and select commands to the electronic system. The input devices  3940  include alphanumeric keyboards and pointing devices (also called “cursor control devices”), cameras (e.g., webcams), microphones or similar devices for receiving voice commands, etc. The output devices  3945  display images generated by the electronic system or otherwise output data. The output devices  3945  include printers and display devices, such as cathode ray tubes (CRT) or liquid crystal displays (LCD), as well as speakers or similar audio output devices. Some embodiments include devices such as a touchscreen that function as both input and output devices. 
     Finally, as shown in  FIG.  39   , bus  3905  also couples electronic system  3900  to a network  3925  through a network adapter (not shown). In this manner, the computer can be a part of a network of computers (such as a local area network (“LAN”), a wide area network (“WAN”), or an Intranet, or a network of networks, such as the Internet. Any or all components of electronic system  3900  may be used in conjunction with the invention. 
     Some embodiments include electronic components, such as microprocessors, storage and memory that store computer program instructions in a machine-readable or computer-readable medium (alternatively referred to as computer-readable storage media, machine-readable media, or machine-readable storage media). Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROM), recordable compact discs (CD-R), rewritable compact discs (CD-RW), read-only digital versatile discs (e.g., DVD-ROM, dual-layer DVD-ROM), a variety of recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW, etc.), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.), magnetic and/or solid state hard drives, read-only and recordable Blu-Ray  discs, ultra density optical discs, any other optical or magnetic media, and floppy disks. The computer-readable media may store a computer program that is executable by at least one processing unit and includes sets of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as is produced by a compiler, and files including higher-level code that are executed by a computer, an electronic component, or a microprocessor using an interpreter. 
     While the above discussion primarily refers to microprocessor or multi-core processors that execute software, some embodiments are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some embodiments, such integrated circuits execute instructions that are stored on the circuit itself. In addition, some embodiments execute software stored in programmable logic devices (PLDs), ROM, or RAM devices. 
     As used in this specification and any claims of this application, the terms “computer”, “server”, “processor”, and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For the purposes of the specification, the terms display or displaying means displaying on an electronic device. As used in this specification and any claims of this application, the terms “computer readable medium,” “computer readable media,” and “machine readable medium” are entirely restricted to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude any wireless signals, wired download signals, and any other ephemeral signals. 
     Although the above description of the various embodiments of the invention show background-rendering operations performed for video, many examples of these background-rendering operations are applicable to rendering audio as well. While the invention has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. In addition, a number of the figures (including  FIGS.  17 ,  18 ,  21 ,  28 , and  30   ) conceptually illustrate processes. The specific operations of these processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. Thus, one of ordinary skill in the art would understand that the invention is not to be limited by the foregoing illustrative details, but rather is to be defined by the appended claims.

Metadata:
Filing Date: 20211012
Publication Date: 20230905
Grant Date: 20230905
Priority Date: 20110216
Inventors: MATSUDA, KEN
DIEPHOUSE, MATTHEW D.
CERF, DAVE
DE MARCO, VINCENZO
MCCOMMONS, JORDAN P.
LASALLE, LOUIS
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/04847", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/048", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04842", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/034", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/2628", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/2622", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04847", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N5/265", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/2625", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/2628", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/031", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/036", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0481", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04842", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0485", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/048", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/034", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04842", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/2628", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 79688568