PATENT DOCUMENT

Publication Number: US-8566721-B2
Application Number: US-43388609-A
Country: US
Kind Code: B2

Title: Editing key-indexed graphs in media editing applications

Abstract:
Some embodiments of the invention provide media editing applications with novel key-indexed graph editing operations. In some embodiments, the media editing application allows a user to modify such a graph without actually selecting any key index on the graph. In some embodiments, the media editing application allows a user to modify the graph by interacting with one or more shapes that are defined in terms of the graph, without selecting any of the key indices that are used to specify the graph.

Claims:
The invention claimed is: 
     
       1. A method of providing a media editing application comprising a graphical user interface (GUI) for editing media content, said method comprising:
 to represent an attribute of a media item along a dimension, defining a key-indexed graph that spans along the dimension, and that comprises (i) at least two key indices at two different locations along the dimension to specify values of the attribute at the two different locations and (ii) a segment between the two key indices that defines a rate of change in the attribute values between the two key indices; and 
 to modify the key-indexed graph without selection of any key indices, defining a selectable region below the key-indexed graph that when selected and moved, remains below the graph but changes a shape of the segment of the key-indexed graph in order to change the rate of change of the attribute values between the two key indices. 
 
     
     
       2. The method of  claim 1 , wherein said media item is a media clip, wherein said media editing application creates a media presentation of the media clip by incorporating the media clip into the media presentation with the attribute values specified by the key-indexed graph. 
     
     
       3. The method of  claim 2 , wherein said media editing application incorporates the media clip into the media presentation by interpolating attribute values in between the key indices based on the shape of the segment. 
     
     
       4. The method of  claim 1 , wherein said media item is a media editing operation. 
     
     
       5. The method of  claim 4 , wherein said media editing operation is a filter operation for creating an effect in a media presentation, wherein said media editing application creates the media presentation in accordance with the attribute values of the filter operation that are specified by the key-indexed graph. 
     
     
       6. The method of  claim 1 , wherein the key-indexed graph spans horizontally along the dimension, wherein selection and movement of the segment of the key-indexed graph between the two key indices along a vertical direction moves the two key indices in unison to modify the attribute values at the two locations by a constant value. 
     
     
       7. The method of  claim 1 , wherein the key-indexed graph comprises a third key index, and another segment between the third key index and one of the two key indices, wherein selection and movement of the segment separates the segment from at least the other segment. 
     
     
       8. The method of  claim 7 , wherein the selection and movement of the segment automatically creates at least one key index adjacent to one of the two key indices in order to create a sudden transition in the attribute values. 
     
     
       9. The method of  claim 1 , wherein the selection and movement of the region changes the shape by forming a curve on the segment of the key-indexed graph. 
     
     
       10. The method of  claim 1  further comprising providing, in said GUI, a preview display area for displaying a real-time preview of the media item in accordance with the attribute values specified by the key-indexed graph. 
     
     
       11. The method of  claim 1 , wherein the media item is a media clip that is part of a composite presentation, the method further comprising defining a composite display area for displaying representations of one or more pieces of media clips that are part of the composite presentation. 
     
     
       12. A method of providing a media editing application comprising a graphical user interface (GUI) for editing media presentations, said method comprising:
 to represent an attribute of a media item along a dimension, defining a key-indexed graph that spans the dimension and that comprises (i) a plurality of key indices at different locations along the key-index graph to specify values of the attribute at the different locations and (ii) a segment between at least two key indices that defines the attribute values between the two key indices; and 
 to modify said key-indexed graph without selection of any key indices, defining a selectable region that remains underneath the segment of the key-indexed graph that when selected (i) creates a new key index on the key-indexed graph at a location about the selected region and (ii) displays on the selected region a representation of the new key index that is movable along the dimension to move the location of the key index along the key-indexed graph. 
 
     
     
       13. The method of  claim 12 , wherein the selectable region is a shape that is formed underneath the segment of the key-indexed graph. 
     
     
       14. The method of  claim 9 , wherein the selection and movement of the region creates the curve by pushing out a first portion of the segment of the key-indexed graph while pulling in a second portion of the segment of the key-indexed graph. 
     
     
       15. The method of  claim 9 , wherein the selection and movement of the region creates a concave or convex curve on the segment of the key-indexed graph. 
     
     
       16. The method of  claim 9 , wherein the selection and movement of the region creates the curve by modifying the angle of tangents at the two key indices. 
     
     
       17. The method of  claim 16 , wherein the amount of modification to the angle of the tangent is weighted depending on a location of the region with respect to the two key indices, wherein when the selected region is closer to a first key index than a second key index, the angle of the tangent at the first key index is modified by a greater amount than at the second key index. 
     
     
       18. The method of  claim 9 , wherein the selection and movement of the region creates the curve by affecting the length of tangents at the two key indices. 
     
     
       19. The method of  claim 18 , wherein the amount of modification to the lengths of tangents at the key indices are weighted such that the movement causes a length of one tangent to become shorter while causing a length of another tangent to become longer. 
     
     
       20. The method of  claim 9 , wherein the curve created by the selection and movement of the region is a parameterizable curve. 
     
     
       21. The method of  claim 20 , wherein the parameterizable curve is one of a bezier curve and a b-spline curve. 
     
     
       22. The method of  claim 9 , wherein said curve defines an interpolation of the attribute values between the two key indices. 
     
     
       23. The method of  claim 12 , wherein the selection of the region causes the new key index to be created on the key-indexed graph at the horizontal coordinate of the selected region. 
     
     
       24. The method of  claim 23 , wherein the key-indexed graph spans along the dimension in a horizontal direction, wherein the representation comprises a line that spans across the region in a vertical direction at the location of the new key index. 
     
     
       25. The method of  claim 24 , wherein the line is movable along the dimension to move the location of the new key index on the key-indexed graph. 
     
     
       26. The method of  claim 12 , wherein the region changes color or pattern based on user-modifications to said key-indexed graph. 
     
     
       27. A non-transitory computer readable medium storing a computer program that when executed by at least one processing unit provides a graphical user interface (GUI), the GUI comprising:
 to represent an attribute of a media item along a dimension, a key-indexed graph that spans along the dimension, and that comprises (i) at least two key indices at two different locations along the dimension to specify values of the attribute at the two different locations and (ii) a segment between the two key indices that defines a rate of change in the attribute values between the two key indices; and 
 to modify the key-indexed graph without selection of any key indices, a selectable region below the key-indexed graph that when selected and moved, does not move above the key-indexed graph but changes a shape of the segment of the key-indexed graph in order to change the rate of change of the attribute values between the two key indices. 
 
     
     
       28. A non-transitory computer readable medium storing a computer program that when executed by at least one processing unit provides a graphical user interface (GUI), the GUI comprising:
 to represent an attribute of a media item along a dimension, a key-indexed graph that spans the dimension and that comprises (i) a plurality of key indices at different locations along the key-index graph to specify values of the attribute at the different locations and (ii) a segment between at least two key indices that defines the attribute values between the two key indices; and 
 to modify said key-indexed graph without selection of any key indices, a selectable region that remains underneath the segment of the key-indexed graph that when selected (i) creates a new key index on the key-indexed graph at a location about the selected region and (ii) displays on the selected region a representation of the new key index that is movable along the dimension to move the location of the key index along the key-indexed graph. 
 
     
     
       29. The non-transitory computer readable medium of  claim 28 , wherein the selectable region is a shape that is formed underneath the segment of the key-indexed graph. 
     
     
       30. The non-transitory computer readable medium of  claim 28 , wherein the key-indexed graph spans along the dimension in a horizontal direction, wherein the representation comprises a line that spans across the region in a vertical direction at the location of the new key index. 
     
     
       31. The non-transitory computer readable medium of  claim 27 , wherein the movement of the selected region toward the segment forms a curve on the segment by pushing out at least a portion of the segment. 
     
     
       32. The non-transitory computer readable medium of  claim 27 , wherein the movement of the selected region away from the segment forms a curve on the segment by pulling in at least a portion of the segment.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application is related to the following applications: U.S. patent application Ser. No. 12/475,601, now published as U.S. Patent Publication 2010/0281404, filed May 31, 2009; U.S. patent application Ser. No. 12/475,602, now issued as U.S. Pat. No. 8,286,081, filed May 31, 2009; and U.S. patent application Ser. No. 12/475,598, now issued as U.S. Pat. No. 8,458,593, filed May 31, 2009. 
     FIELD OF THE INVENTION 
     The invention relates to editing key-indexed graphs in media editing applications. 
     BACKGROUND OF THE INVENTION 
     To date, many media editing applications have been proposed for editing digital graphic design, image editing, audio editing, and video editing. These applications provide graphical designers, media artists, and other users with the tools for creating and editing media presentations. Examples of such applications include Final Cut Pro® and iMovie®, both sold by Apple Computer, Inc. 
     Several of the media editing applications provide editing tools that allow its user to perform keyframe editing. Typically, keyframe editing entails manipulating keyframes, which are control points that are associated with a particular location in a media clip.  FIG. 1  illustrates manipulating keyframes  105  and  110  to perform keyframe editing. Here, to modify an attribute value at a first keyframe, the user selects the keyframe  105  and drags the keyframe to a new location. To make the attribute values at a second keyframe match the first keyframe, the user repeats the steps described above for the keyframe  110  and aligns the two keyframes  105  and  110 . 
       FIG. 2  illustrates an example of another existing keyframe editing operation. This operation performs an interpolation between the first and second keyframes by manipulating Bezier handles on the keyframes  105  and  110 . Specifically, to create the interpolation, the user (i) selects the keyframe  105  such that handles  205  and  210  appear; (ii) selects the handle  210 ; (iii) adjusts the handle  210  to create a first portion of an inner curve adjacent to the keyframe  105 ; (iv) selects the keyframe  110  such that handles  215  and  220  appear; (v) selects the handle  215 ; and (vi) adjusts the handle  215  to create a second portion of the inner curve adjacent to the keyframe  110 . 
     A number of shortcomings exist in the keyframe editing described above. One such shortcoming is that a user of media editing application must know how to manipulate multiple keyframes with a certain amount of precision to create even a simple effect. Furthermore, the user must not only understand how to manipulate Bezier handles but also possess the patience and drawings skills to use them to create a desired interpolation between keyframes. 
     Therefore, there is a need for a more simplified way of performing keyframe editing. Also, there is a need for a media editing application that allow its user to perform simple to complex keyframe editing with minimal drawing skills and without having to understand how Bezier handles work. 
     SUMMARY OF THE INVENTION 
     Some embodiments of the invention provide media editing applications with novel key-indexed graph editing operations. Some media editing applications use key indices (e.g., keyframes) to define a graph that specifies the value of an attribute of a media clip or an attribute of an editing operation over a duration (e.g., a duration of time, a duration of frequencies, etc.). In some embodiment, the media editing application allows a user to modify such a graph without actually selecting any key index on the graph. For example, some embodiments allow the user to directly select the graph and modify it by moving the selected part of the graph to a new location. 
     In conjunction with this graph selection capability, or instead of it, some embodiments also allow a user to modify the graph by interacting with one or more shapes that are defined in terms of the graph, without selecting any of the key indices that are used to specify the graph. For instance, in some such embodiments, the user can select an interior location within the shape and move it in order to modify the graph. 
     Some embodiments also allow the user to specify a location for a new key index by selecting an interior location within the shape. For instance, in some such embodiments, when the user selects the interior location of the shape, it causes a new key index to be created on the graph at the horizontal coordinate of the selected location. When a key index is created, some embodiments create and display on the shape a representation of the key index, which the user can select and move in order to cause the key index to be relocated to a new location on the graph. One example of such a representation in some embodiments is a line that spans the shape at the location of the key index. This line can be viewed as dividing the shape into two distinct shapes. Alternatively, as further described below, such a line can simply be viewed as only a selectable control within the shape. Irrespective of its characterization, this line in some embodiments can be used to modify the key-index location, to modify the graph and shape, and/or to place bounds on modifications to the shape and the graph. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the invention are set forth in the appended claims. However, for purpose of explanation, several embodiments of the invention are set forth in the following figures. 
         FIGS. 1-2  illustrate conventional keyframe editing. 
         FIG. 3  illustrates an example of a line graph that is initially shown in a key-index graph editing window. 
         FIG. 4  illustrates an example of modifying a graph by interacting with a rectangular shape. 
         FIG. 5  illustrates an example of moving a key index to a new location on a graph without selecting and moving the key index. 
         FIG. 6  illustrates an example of selecting modifying graphs without selecting any key index. 
         FIG. 7  illustrates an example of forming a curve on a graph by interacting with a modified shape. 
         FIG. 8  provide an illustrative example of a graphical user interface (“GUI”) of a media editing application with a graph editor. 
         FIGS. 9A and 9B  illustrate an example modifying a graph using the GUI that is illustrated in  FIG. 8 . 
         FIG. 10  illustrates a process that a media editing application performs in response to user input. 
         FIG. 11  conceptually illustrates an example of populating a graph editing window with key-indexed graphs. 
         FIG. 12  illustrates creating a new key index by selecting an interior location within a shape that is defined by a graph. 
         FIG. 13  illustrates an example of selecting a location on a graph editor in order to create two new key indices. 
         FIG. 14  illustrates an example of altering the selection state of several key-indexed graphs. 
         FIG. 15  illustrates an example of creating several key indices across selected key-indexed graphs. 
         FIG. 16  illustrates a process of some embodiments for creating one or more new key indices. 
         FIG. 17  illustrates relocating a key index on the graph by selecting and moving a representation of the key index on a shape. 
         FIG. 18  illustrates another example of relocating a key index on a graph by selecting and moving a representation of the key index. 
         FIG. 19  illustrates relocating key indices on the graph by selecting and moving an interior location within a shape. 
         FIG. 20  illustrates relocating a key index on a graph by selecting and moving an interior location within the shape 
         FIG. 21  illustrates relocating a key index by selecting and moving a symbol on a graph editor. 
         FIG. 22  illustrates relocating two aligned key indices by selecting and moving a symbol that represent the two aligned key indices. 
         FIG. 23  illustrates an example of modifying the location of several overlapping key indices by selecting several graphs and moving a representation on a graph editor. 
         FIG. 24  illustrates a process of some embodiments for relocating one or more key indices. 
         FIG. 25  illustrates an example of selectively modifying a graph without selecting any key index. 
         FIG. 26  illustrates modifying a graph by selecting a key index on the graph. 
         FIG. 27  conceptually illustrates a process of some embodiments for setting attribute value at one or more key indices. 
         FIGS. 28-29  provide an illustrative example of forming a curve on a graph by selecting and moving an interior location in a vertical direction. 
         FIGS. 30-31  illustrate examples of forming a curve on a graph by moving an interior location in a horizontal direction. 
         FIGS. 32-33  illustrate several examples of modifying the angle of the tangents at key indices. 
         FIGS. 34-35  illustrate several examples of the affecting the lengths of tangents at key indices by selecting and moving an interior location horizontally. 
         FIG. 36  illustrates a process of some embodiments for creating a curve on a graph by selecting and moving an interior location within a shape that is defined by the graph. 
         FIG. 37  illustrates an example of receiving selection of a section of a graph for independent modification. 
         FIG. 38  illustrates moving a section of the graph vertically to separate the section from other neighboring sections of the graph. 
         FIG. 39  illustrates realigning a section of a graph with several other neighboring sections. 
         FIG. 40  illustrates a process of some embodiments for selecting and modifying a section of a graph independently of a neighboring section. 
         FIG. 41  conceptually illustrates the software architecture of an application of some embodiments. 
         FIG. 42  conceptually illustrates a data structure of a key-indexed graph of some embodiments that may be displayed in a display area of a graphical user interface. 
         FIG. 43  conceptually illustrates a process of some embodiments for defining an application. 
         FIG. 44  conceptually illustrates a computer system with which some embodiments of the invention are implemented. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     Some embodiments of the invention provide media editing applications with novel key-indexed graph editing operations. Some media editing applications use key indices to define a graph that specifies the value of an attribute of a media clip or an attribute of an editing operation over a duration (e.g., a duration of time, a duration of frequencies, etc.). In some embodiment, the media editing application allows a user to modify such a graph without actually selecting any key index. For example, some embodiments allow the user to directly select the graph and modify it by moving the selected part of the graph to a new location. 
     In conjunction with this graph selection capability, or instead of it, some embodiments also allow a user to modify the graph by interacting with one or more shapes that are defined in terms of the graph, without selecting any of the key indices that are used to specify the graph. Some embodiments provide this graph-selection and shape-selection capability, by defining the key-indexed graph and its associated shape as selectable and modifiable items in the graphical user interface (UI) of the media editing application (i.e., as items that can be selected and modified by the user in the UI). Some of these embodiments also define the key indices as selectable items in the UI, while other embodiments do not. 
     Several examples of such embodiments will be initially described below by reference to  FIGS. 3-7 . However, before describing these initial examples, several terms are defined. In some media editing applications, a key index represents a value (e.g., a default value or a user-specified value) of a clip&#39;s or an operation&#39;s attribute at a particular location along a particular duration. For example, in a fade to black effect for a video clip, a starting key index might represent one point during a duration when an opacity attribute starts to change from fully visible to fully transparent, and an ending key index represents another transitional point during the duration when the change ends. A graph is typically defined between two key indices (e.g., starting key index, ending key index) in order to define a transition that specifies the speed and/or ease at which the attribute value changes. In some cases, the transition between two key indices is linear (e.g., gradual, swift). The transition between the two key indices may also be nonlinear (e.g., exponential). 
     Media editing applications can use such key indices and graphs to specify the transitioning values of any attribute associated with the edited media content (e.g., media clips) or the editing operations. Different types of media content may have different attributes. For instance, attributes of a video clip may include opacity, axis, color, and scale, while attributes of an audio clip may include volume level, echo, and pan. Moreover, the duration across which the attributes are defined may differ. They may differ in length or in type (e.g., the duration might be expressed in time, or in frequency, or along a different axis). 
     For some embodiments of the invention,  FIGS. 3-7  illustrate several examples of editing a key-indexed graph by modifying the graph without directly selecting the key indices that define the graph. These examples illustrate five different stages of editing a key-indexed graph in a media editing application. For purposes of simplifying the description of these figures, only the key-index graph editing window  300  of the media editing application is shown in these figures. Several more detailed embodiments will be described below for presenting a key-index graph editing window in a media editing application. 
       FIG. 3  illustrates a line graph  315  that is initially shown in the key-index graph editing window  300 . As shown in this figure, the line graph is defined by reference to two key indices  305  and  310 . This graph represents the value of an attribute (e.g., opacity, position, volume level) of a media clip (e.g., audio clip, video clip, text overlay, picture, and/or other media) over a duration of time. This graph also defines a rectangular shape  320  within the window  300  of the media editing application; in other words, the rectangle  320  is initially defined underneath the graph  315 . Also, in this example, a timeline (not shown) spans across the window  300 . One or more media tracks (not shown) span along this timeline. Each track is for holding one or more media clips, with each clip lasting a particular duration. 
       FIG. 4  illustrates an example of modifying the line graph  315  by interacting with the rectangular shape  320 . Specifically, it illustrates that the cursor selection of (e.g., a double click operation within) an interior location  435  within the rectangular shape  320  creates a new key index  405  that divides the line graph  315  into two new portions, line graphs  410  and  415 . Specifically, this cursor selection creates the new key index  405  about the horizontal location  435  of the cursor. The new key index  405  defines the new line graph  410  along with the key index  305 , and defines the new line graph  415  along with the key index  310 . 
     The media editing applications of different embodiments treat differently the division of the line graph  315  into the two line graphs  410  and  415 . For instance, some embodiments discard the line graph  315  and only use the two line graphs  410  and  415  as selectable elements in the graphical user interface of the media editing application. Other embodiments, however, use the new graphs  410  and  415  as conceptual, pictorial representations of the division of the graph  315 ; in other words, these embodiments maintain the line graph  315  as the selectable element in the GUI, and use the new key index  405  for placing bounds on the modifications that are received directly or indirectly with respect to the line graph  315 . 
     When a key index is created on a graph, some embodiments create and display on a shape that is defined by reference to the graph a representation of the key index. This representation can then be selected and moved in order to cause the key index to be relocated to a new location on the graph. One example of such a representation in some embodiments is a line that spans the shape at the location of the key index. For instance, in  FIG. 4 , the selection of the interior location of the rectangular shape  320  causes a line  420  to appear on the shape. This line  420  can be viewed as dividing the shape  320  into two distinct shapes  425  and  430 . Alternatively, this line  420  can simply be viewed as only a selectable control within the shape. 
     Irrespective of its characterization, this line  420  in some embodiments can be used to modify the location of the key index  405 , to modify the graph and shape, and/or to place bounds on modifications to the shape and the graph. For instance,  FIG. 5  illustrates an example of moving the key index  405  to a new location on the graph  315  without selecting and moving the key index. Specifically, it illustrates that the cursor selection and movement (e.g., a cursor click and drag operation) of the line  420  along a horizontal direction causes the key index  405  to be moved with the line. The movement also redefines the graphs  410  and  415 , as it reduces the distance between the key indices  405  and  310  while distancing the key indices  305  and  405 . In other words, the horizontal movement causes the transitional period between the key indices  305  and  405  to increase while causing the transitional period between the key indices  405  and  310  to decrease. 
       FIG. 6  illustrates an example of selectively modifying the graph  315  without selecting any key index. In this example, the graph  315  is modified through the cursor selection and vertical movement  605  (e.g., a cursor click and drag operation) of a part of the line graph  415  that is defined between the two key indices  405  and  310 . The vertical movement  605  also causes the rectangular shape  430  that is defined the line graph  415  to be resized. As the key index  405  represents one of the vertices of the line graph  410 , the vertical movement  605  further (1) modifies the slope of the line graph  410 , and (2) causes the shape  425  to lose its rectangular shape and become trapezoidal. 
       FIG. 7  illustrates an example of modifying the key-indexed graph  315  by interacting with a shape that is defined by reference to this graph. In this example, an interior location  705  within the shape  425  is selected and moved vertically (e.g., through a click and drag operation) towards the line graph  410 . This selection and movement of the interior location causes a curve to be formed on the line graph  410 . In some embodiments, the cursor selection and movement of the interior location creates a smooth curve by pushing out or pulling in a part of the line graph while smoothing out other parts. For instance, in  FIG. 7 , the selection and movement creates the smooth curve by pushing out a part of the line graph  410  about the selected interior location while at the same time pulling in a part adjacent to the key index  305 . 
     The examples illustrated in  FIGS. 3-7  were described above to include certain features. However, one of ordinary skill will realize that not all these features need to be used together. For instance, some embodiments might allow an interior location of a shape to be selected in order to create key indices but might not allow it to be manipulated in order to create a curve. Similarly, some embodiment might allow a key-indexed graph to be selected and moved anywhere along its duration but might not allow a representation of a key index (e.g., line) to be selected and moved. 
     Several more detailed examples of manipulating key-indexed graphs will be described below. However, before describing these examples, an exemplary media editing application that implements the graph editing operations of some embodiments will be described below in Section I. Section II then describes several examples of populating a graph editor with several key-indexed graphs. Section II also describes several examples of manipulating key-indexed graphs using a graph editor. Section III follows that discussion with a description of the software modules and data structures used to implement some embodiments of the media editing application. Lastly, Section IV describes a computer system which implements some embodiments of the invention. 
     I. Media Editing Application 
       FIG. 8  illustrates a graphical user interface (“GUI”)  800  of a video editing application that uses the novel key-indexed graph editing operations of some embodiments of the invention. As shown in these figures, the GUI  800  includes a preview display area  850 , a composite display area  805 , an attribute display area  810 , a timeline  820 , and a media browser  815 , and a graph editor  840  with a graph editing window  875 . 
     The preview display area  850  displays the preview of the media presentation that the media editing application creates. The composite display area  805  provides a visual representation of the composite presentation being created by the application&#39;s user. It displays one or more geometric shapes that represent one or more pieces of media content that are a part of the media presentation. In the example illustrated in  FIG. 8 , the composite display area  805  is an area that includes multiple media tracks that span across the timeline  820 . One or more pieces of media content can be placed on each track. 
     The attribute display area  810  is an area in the GUI  800  through which the application&#39;s user can view attributes of media content in the media presentation, or media editing operations for the media presentation. The user can select one or more attributes in this area  810 . For some or all attributes, such a selection will cause an editable graph to be presented in the graph editing window  875  in order to allow the user to view and possibly edit the graph. The attribute display area  810  also provides various user interface tools  855  (e.g., list boxes, text fields, buttons, radial dials, etc.) for modifying the attributes. 
     The timeline  820  represents a duration or a portion of the duration in the media presentation. A time marker (also called a playhead)  835  is situated on the timeline  820 . The user of the media editing application can drag the time marker along the timeline to display a preview of the media presentation at a particular point in the presentation, or to play the preview starting from the particular point by selecting the play button  825 . 
     The media browser  815  is an area in the GUI  800  through which the user can view media content in the media presentation. For instance, in  FIG. 8 , the media browser lists several items that represent the different pieces in the media presentation. In some embodiments, these items are organized hierarchically, and several of the items may be selected to hide or reveal one or more of the pieces. 
     The graph editor  840  is the area in the application that displays the graph editing window  875 . This window  875  displays one or more key-indexed graphs that can be modified by a user according to one or more of the novel graph editing operations of some embodiments of the invention. In the example illustrated in  FIG. 8 , the window  875  displays the graph  845  that is associated with a scale attribute of the media content over a particular duration of the media presentation. The graph editor shows this association by (i) displaying a description  865  of the attribute and (ii) displaying the key-indexed graph  845  over a particular duration in the timeline  820 . 
     In the example illustrated in  FIG. 8 , the key-indexed graph  845  is provided in a separate window  875  that is dedicated for displaying such graphs in the media editing application. However, in some embodiments, one or more such graphs may be provided in another window in the media editing application. For instance, in some such embodiments, one or more such graphs may be shown in the composite display area  805  with the clip representations (e.g., on top of, adjacent to, the clip representations). 
     To describe the operation of the video editing application of  FIG. 8 ,  FIG. 10  illustrates a process  1000  that the video editing application performs in response to user input, while the user uses the application and its graph editing operations to create a media presentation. The number and sequence of operations in this process are arbitrary as the user might perform any number of operations in any sequence to create a presentation. The process  1000  of  FIG. 10  will be described by reference to  FIG. 8 ,  FIGS. 9A and 9B , which show the GUI  800  at two different stages during an editing session than  FIG. 8 .  FIG. 8  illustrates the GUI  800  before receiving a modification to a key-indexed graph  845  that is illustrated in the graph editing window  875 , while  FIGS. 9A and 9B  illustrate it after receiving the modifications. 
     The process  1000  begins at  1005  when it receives input to a create media presentation project. In some embodiments, the media presentation project is a file that stores data about a media presentation. For examples, the project can include data such as a title, time code data, a media content&#39;s start and end time, a media content&#39;s attribute settings, filter settings, etc. The project may be created in a number of different ways. For instance, it may be created by a user selecting a menu item such as a “new project” item from a pull-down menu, selecting a toolbar icon, selecting a shortcut key, etc. 
     The process then adds (at  1010 ) media content to the media presentation project. In some embodiments, this is initiated by receiving a user&#39;s selection of one or more pieces of media content. For instance, the media presentation of  FIG. 8  is a composite presentation that is formed by several pieces of media content that are illustrated on several different tracks of the composite display area  805 . 
     At  1015 , the process then displays attributes of the media content. The attributes of the media content may be displayed in a variety of different ways. For instance, in  FIG. 8 , the attributes of the video clip are listed in the attribute display area  810 . These listed attributes include opacity, rotation, position, scale, and axis. In some embodiments, the media editing application displays the attributes when a user selects a representation of a piece of media content in a GUI. For instance, in  FIG. 8 , the attributes of the video clip may be displayed in the attribute display area  810  by selecting one of the representations on a track of the composite display area  805 . 
     At  1020 , the process populates a graph editor with one or more key-indexed graphs. Different embodiments populate the graph editor differently. For instance, in the example illustrated in  FIG. 8 , the graph editor  840  may be populated with the graph  845  by the user selecting a description  860  of the attribute in the attribute display area  810 , and dragging and dropping it in the graph editor. The graph editor may also be populated by the user selecting an icon  870 . 
     The process  1000  then receives (at  1025 ) modification to one or more of the key-indexed graphs. A graph (like graph  845 ) that is displayed in the graph editor can be modified when the user adjusts one of the user interface tools  855  (e.g., list boxes, text fields, buttons, radial dials, etc.). For instance, the user can drag the time marker  835  along the time line  820  to a particular point in time and modify the scale of the video clip at the particular point in time by directly adjusting a list box control  880  and/or a text box control  885 . 
     A graph (like graph  845 ) that is displayed in the graph editor may also be modified by a user interacting with the graph in accordance with any one of the editing operations described above or below.  FIGS. 9A and 9B  illustrate one example of such an editing operation. Specifically,  FIG. 9A  illustrates the graph  845  after a new key index  905  has been created in response to a user&#39;s selection (e.g., through a cursor click operations such as a double click) of an interior location of within a shape  915  associated with the graph  845 . 
       FIG. 9B  then illustrates the graph  845  after the user has selected and moved downwards (e.g., though a cursor click and drag operation) the portion of the graph to the right of the key index  905 . The selection and movement causes the scale attribute across a portion of the graph starting from the key index  905  and ending at key index  910  to be reduced by a constant value. Also, as the key index  905  represents an ending index for a portion of the graph starting from a key index  920 , the movement creates a negative slope on the portion. This result in the scale attribute starting normally at the key index  920  and transitioning to about half at the key index  905 . In  FIG. 9B , this reduction in scaling value is pictorially illustrated as the smaller size of the clip that is displayed in the preview display area for the specified playhead  835  location. 
     At  1030 , the process  1000  then creates the media presentation based on one or more of the key-indexed graphs. In some embodiments, the media editing application creates the media presentation by compositing the media content into the media presentation with the attribute values defined by one or more of the graphs. For instance, in some such embodiments, to composite the media content, the media editing application identifies attribute values at key indices and any transition between the key indices. The media editing application then composites the media content by interpolating the attribute values between the key indices according to one or more of the identified transitions. Lastly, the process (at  1035 ) saves the media project and ends. 
     Although though the process  1000  is described by reference to  1005 - 1035 , one of ordinary skill in the art would understand that the process may not be performed in the same order, or may exclude one or more operations. For instance, a user of the media editing application may intersperse the graph editing operations with iterative selections of and edits to the media content. 
     II. Key-Indexed Graph Editing 
     As mentioned above, some embodiments provide several novel key-indexed graph editing operations for manipulating one or more key-indexed graphs. Several different examples of operations for modifying one or more key index graphs will be described below. In some cases, these different operations may be used conjunctively (i.e., all together) in one application, while in other cases, some of the operations may be alternatives to one another. When these operations are used conjunctively in one application, some embodiments allow a user to differentiate one operation from another operation by providing user interface tools, user interface techniques, and/or shortcuts (e.g., through the use of hotkeys). This will be further elaborated in the examples described below. Several examples of populating and manipulating the key-indexed graphs will now be described by reference to  FIGS. 11-40 . 
     A. Populating a Graph Editing Window 
       FIG. 11  conceptually illustrates an example of populating a graph editing window  1115  with key-indexed graphs  1120 - 1130 . In this example, a user of the media editing application populates the window  1115  with graphs associated with two different types of media content (i.e., video content, audio content) in a media project. Specifically, to populate the window, the user first selects a video clip  1105  in the composite display area  1130  of a media editing application, and then for this video clip, selects an opacity attribute in an attribute display area  1135  in order to populate it with the graph  1120 . The user then selects a rotation attribute in the attribute display area  1135 , in order to populate the window with the graph  1125 . The user also selects an audio clip  1110  in the composite display area  1130 , and then selects a level attribute in the attribute display area  1135 , in order to populate the window with the graph  1130 . 
       FIG. 11  also illustrates that the graph editing window  1115  may be populated with one or more key-indexed graphs associated other attributes of an editing operation. Specifically, the figure illustrate that the window may be populated with editing operation attributes such as filters. Filters, in some embodiments, are media editing components that may be associated with a piece of media content to create an effect. For instance, a color correction filter may be applied to a video clip, in order to adjust the color of the video clip; similarly, a twirl filter creates a twirling effect on the video clip, a blur filter creates a blurring effect on the video clip, etc. An audio clip may also be associated with filters, such as an echo filter that creates an echo, noise reduction filter that reduces noise, pass band filter that allows a range of frequencies to pass through while preventing other frequencies, etc. 
     In some embodiments, instead of manually populating a graph editor, the media editing application automatically populates the graph editor with one or more key-indexed graphs. For instance, in some such embodiments, when a user of the media editing applications selects a media content for a media presentation, the user is automatically presented with a graph editor that includes several key-indexed graphs associated with attributes of the media content. 
     B. Creating Key Indices 
       FIGS. 12-15  illustrate several examples of creating new key indices. Specifically, these figures illustrate creating new key indices by (i) selecting an interior location within a shape that is defined by a graph displayed in a graph editor window or (ii) selecting a location on the graph editor that is outside of the window. In these and other examples that follow, a graph editor  1200  includes a graph editing window  1240 . The window displays graphs  1215  and  1220 . The graph  1215  is associated with an opacity attribute of a media clip over a duration and defines a shape  1205 , while the graph  1220  is associated with a scale attribute of the media clip over the duration and defines a shape  1260 . 
       FIG. 12  illustrates creating a new key index  1225  by selecting an interior location within the shape  1205  that is defined by the graph  1215 . Similar to the example described above, this figure illustrates a cursor  1265  as performing a cursor selection of (e.g., a double click operation within) an interior location  1270  of the shape. It further illustrates that this selection causes the graph to divide into two portions (i.e., graphs  1230  and  1245 ) about the horizontal location of the cursor. As mentioned above, the media editing applications of different embodiments treat differently the division of the graph  1215  into the two line graphs  1230  and  1245 . For instance, some embodiments discard the line graph  1215  and only use the two line graphs  1230  and  1245  as selectable elements in the graphical user interface of the media editing application. Other embodiments, however, use the new graphs  1230  and  1245  as conceptual, pictorial representations of the division of the graph  1215 ; in other words, these embodiments maintain the graph  1215  as the selectable element in the GUI, and use the new key index  1225  for placing bounds on the modifications that are received directly or indirectly with respect to the line graph  1215 . 
     When a key index is created on a graph, some embodiments create and display on a shape that is defined by reference to the graph a representation of a key index. This representation can then be selected and moved in order to cause the key index to be relocated to a new location on the graph. One example of such a representation in some embodiments is a line that spans the shape at the location of the key index. For instance, in  FIG. 12 , the selection of the interior location of the shape  1205  causes a line  1235  to appear on the shape. This line  1235  can be viewed as dividing the shape  1205  into two distinct shapes  1210  and  1255 . Alternatively, this line  1235  can simply be viewed as only a selectable control within the shape. 
     The media editing applications of different embodiments treat differently the division of the shape  1205  into the two shapes  1210  and  1255 . For instance, some embodiments discard the shape  1205  and only use the shapes  1210  and  1255  as selectable elements in the graphical user interface of the media editing application. Other embodiments, however, use the new shapes  1210  and  1255  as conceptual, pictorial representations of the division of the shape  1205 ; in other words, these embodiments maintain the shape  1205  as the selectable element in the GUI, and use the new line  1235  and/or the key index  1225  for placing bounds on the modifications that are received directly or indirectly with respect to the shape  1205 . 
     Instead of displaying a representation on a shape, or in conjunction with this, some embodiments display a representation of a new key index on a graph editor. For instance,  FIG. 12  illustrates that when the key index  1225  is created, a symbol  1210  that represents the key index is displayed on the graph editor  1200 . Specifically, the symbol is displayed on the graph editor at the horizontal coordinate of the key index. Similar to the line on the shape of the graph, the representation in some embodiments is a selectable graphical user interface item that the user can select and move in order to cause the key index to be relocated to a new location on the graph. 
       FIG. 13  illustrates an example of selecting a location on the graph editor  1200  outside of the window  1240  in order to create two new key indices  1305  and  1325 . Specifically, it illustrates the cursor  1265  as selecting (e.g., through a double click operation) one location  1330  on the graph editor  1200 . As shown in  FIG. 13 , this selection creates two new key indices  1305  and  1325 , where one key index  1305  is associated with opacity graph  1215 , while the other key index  1325  is associated with the scale graph  1220 . In this example, the new key indices are created across the graphs  1215  and  1220  about the horizontal coordinate of the selected location. Also, two new lines  1315  and  1320  that correspond to the two new key indices are displayed across the graphs  1215  and  1220  about the horizontal coordinate of the selected location. 
     In some embodiments, when multiple new key indices are created at a same location along the duration on multiple graphs, some embodiments display one representation for the multiple key indices on a graph editor. For instance, in  FIG. 13 , as the two new key indices  1305  and  1325  are created at a same location along the duration, the selection causes one symbol  1310  that represents both the two key indices to be displayed on the graph editor  1200 . Some embodiments also use such a representation when two key indices that were created at two different times for two different graphs subsequently overlap in time. 
     In some cases, a user of the media editing application may not want to manipulate multiple different graphs together as one. For instance, when multiple key-indexed graphs are displayed in a graph editor, the user may want to create key indices across only some but not all of the graphs through a single selection of a location on a graph editor. Accordingly, some embodiments allow the user to choose one or more key-indexed graphs to modify. In some such embodiments, the user can select or deselect a graph for modification by altering its selection state. 
       FIG. 14  illustrates altering the selection state of several key-indexed graphs. As shown, in addition to the opacity graph  1215  and the scale graph  1220 , a graph  1405  that is associated with position of the media clip is displayed in the graph editing window  1240 . In this example, the selection states of two of the graphs are altered. Specifically, the user alters the selection states by first selecting the opacity graph  1215  and then selecting the position graph  1405 . The graphs  1215  and  1405  may be selected in any number of different ways. For instance, the user may select the graphs  1215  and  1405  through a cursor click operation while holding down a modifier key, by selecting user-interface controls (e.g., check boxes), through hotkeys (e.g., CTRL+A), etc. 
       FIG. 15  illustrates an example of creating key indices only across the selected graphs  1215  and  1405 . Specifically, it illustrates the cursor  1265  as selecting (e.g., through a double click operation) one location  1505  on the graph editor  1200 . As shown, this selection creates two new key indices, where one key index  1510  is associated with opacity graph  1215 , while the other key index  1515  is associated with the position graph  1405 . However, the cursor selection of the location  1505  does not cause a new key index to be created for the scale graph  1220  as it is not one of the selected graphs. 
     The preceding section described and illustrated various ways to create new key indices.  FIG. 16  conceptually illustrates a process  1600  of some embodiments for creating one or more new key indices. Process  1600  is performed by a media editing application in some embodiments. The process  1600  starts at  1605  when it displays one or more key-indexed graphs. Several examples of displaying such key-indexed graphs are illustrated in  FIGS. 12-15 . 
     The process  1600  then receives (at  1610 ) input to create one or more of the new key indices. In some embodiments, the input is received from the user interacting with a graphical user interface of the media editing application. At  1615 , the process determines whether a graph (e.g., an interior location within a shape defined by the graph) is selected or another location on a graph editor is selected. An example of receiving a user&#39;s selection of a graph that is displayed in a graph editing window of a graph editor is described above by reference to  FIG. 12 . On the other hand, an example of receiving selection of a location on the graph editor that is outside of the graph editing window is described above by reference to  FIG. 13 . 
     When the graph is selected, the process  1600  proceeds to  1620 ; otherwise it proceeds to  1645 . At  1620 , the process  1600  identifies the selected location on the graph. In some embodiments, such identification entails determining the input coordinate of the selected location. At  1625 , the process then determines a location on the graph for the new key index based on the selected location. For instance, when the user selects the interior location of a shape that is defined by the graph, some embodiments determine the location for the new key index at the horizontal coordinate of the selected location. At  1630 , the process  1600  then creates the new key index on the graph at the determined location. 
     When the determination is made (at  1615 ) that the graph editor is selected, the process  1600  proceeds to  1645 . The process identifies (at  1645 ) the selected location on the editor. In some embodiments, such identification includes determining the input coordinate of the selected location. At  1650 , the process then identifies one or more graphs that are to be modified as a result of the selection. Several examples of performing such identifications are described above by reference to  FIGS. 13-15 . 
     The process  1600  then determines (at  1655 ) a location for each new key index on each identified graph based on the selected location of the graph editor. For instance, when the user selects the location on the graph editor, some embodiments determine the location for each new key index at the horizontal coordinate of the selected location. The process  1600  then creates (at  1660 ) a new key index for each identified graph. 
     When one or more key indices are created, the process  1600  assigns (at  1635 ) attribute value for each new key index. In some embodiments, one or more of the new key indices are assigned a default value. For instance, when the new key index represents an opacity attribute, it might be assigned a value that defines the opacity as fully visible. Some embodiments assign a value at the key index that is equal to the value of the attribute at the horizontal coordinate of the key index before the creation of the key index. That is, the creation of the key index does not alter the attribute of the graph at that point. The process  1600  then awaits ( 1640 ) input to create more new key index. When such input is received, the process returns to  1615 . Otherwise, the process ends. 
     One of ordinary skill in the art will realize that not all features for creating key indices need to be used together. Accordingly, some embodiments perform variations on the process  1600 . For example, some embodiments might not allow the user to specify a location for new key indices by selecting on a part of a graph editor that is outside of a graph editing window. Hence, in some such embodiments, the process  1600  might only include the operations for creating a new key index when a graph is selected. Furthermore, in some embodiments, the operations of process  1600  might be performed by two or more separate processes. That is, some embodiments could have one process for creating a new key index through selection of the graph and a separate process for creation of a new key index through selection within the graph editor. 
     C. Relocating Key Indices 
       FIGS. 17-23  provide several illustrative examples of relocating key indices on one or more key-indexed graphs. Specifically, these figures illustrate relocating key indices by selecting and moving: (i) a representation of a key index on a shape that is defined by a graph, (ii) an interior location within such a shape, and (iii) representations of key indices on a graph editor that are outside of a graph editing window. 
       FIG. 17  illustrates relocating the key index  1305  on the graph  1215  by selecting and moving a representation of the key index on the shape  1205  that is defined by the graph. Specifically, to relocate the key index  1305 , this figure illustrates selecting and moving the line  1315  on the shape  1205  that is associated with the graph  1215 , which was described above by reference to  FIG. 13 . In this example, when a user selects the line  1315  (e.g., through a cursor click operation), the user is presented with a directional arrows  1705  that indicate that the line is selected and can be moved in two different directions. The user then moves the line (e.g., through a cursor drag operation) to relocate the key index on the graph, as shown in  FIG. 17 . 
     When several key indices for several graphs overlap (i.e., are at the same point in the timeline), some embodiments display on the graph editor  1200  one representation for the several key indices, as mentioned above. When one of the two overlapping key indices is moved, some embodiments change the representation in the graph editor to signify that the two key indices are no longer overlapping. One such example is illustrated in  FIG. 17 . Specifically, this figure illustrates an example of the graph editor  1200  after relocating one of two overlapping key indices  1305  and  1325 . As shown in this figure, the selection and movement of the line  1315  separates the key indices  1305  and  1325  in time, and thereby causes the symbol  1310  on the graph editor to be replaced by two separate symbols, namely a first symbol  1715  that represents the key index  1305  and a second symbol  1710  that represents the key index  1325 . 
       FIG. 18  illustrates another example of relocating a key index on the opacity graph  1215  by selecting and moving a representation of the key index. However, in this example, prior to the selection and movement of the representation, the user has created a sloped transition on a portion  1810  of the graph in between a beginning key index  1805  and the key index  1225 . The user has created the sloped transition by selecting and moving a portion  1820  of the graph to the right of the key index  1225 . As shown in  FIG. 18 , when the user selects and moves the line  1235  horizontally (e.g., through a cursor click and drag operation), the movement causes the transitional period between the key indices  1805  and  1225  to increase. This increase in the transitional period redefines the sloped transition. Specifically, the sloped transition is redefined such that the opacity attribute changes more gradually over the transitional period between the key indices  1805  and  1225 . 
       FIG. 19  illustrates relocating the key indices  1225  and  1305  on the graph  1215  by selecting and moving an interior location  1915  within the shape  1205 . In this example, the selection of the interior location causes directional arrows  1905  to be displayed in the graph editing window  1240 . These arrows indicate that the interior location is selected and can be moved in two different directions. The user then moves the selected interior location (e.g., by moving the cursor  1920 ). This movement causes both the key indices  1225  and  1305  and their corresponding lines  1235  and  1315  to be moved horizontally along the graph. 
     This movement can be implemented differently in different embodiments. For instance, some embodiments divide the shape  1205  into three smaller shapes based on the two lines  1235  and  1315 . Some such embodiments then implement this move by moving the smaller shape  1910  whose interior the user selects. Other embodiments might not divide the shape  1205  into smaller shapes, or might divide it but not use that division implementing the operation illustrated in  FIG. 19 . Some of these embodiments implement this operation by simply relocating the key indices  1225  and  1305 , and their associated lines  1235  and  1315 , based on the duration of the drag operation that the user performs on the interior location  1915  in the shape  1205 . 
       FIG. 20  illustrates relocating the key index  1225  on the graph  1215  by selecting and moving an interior location  2010  within the shape. The selected interior location is adjacent to the key indices  1225  and  2005 . In this example, the cursor selection and horizontal movement of the interior location  2010  causes the key index  1225  to be moved horizontally along the graph. However, the selection and movement does not affect the key index  2005 . Some embodiments allow a left-most key index and/or right-most key index to persist (e.g., infinitely) beyond the boundaries of a graph display area. For instance, in  FIG. 20 , a horizontal cursor movement of the selected interior towards the key index  2005  might cause it to be moved past the boundaries of the graph editing window  1240 . 
       FIGS. 21-22  illustrate relocating one or more key indices by selecting and moving representations on the graph editor  1200  that are outside of the graph editing window  1240 . Specifically,  FIG. 21  illustrates relocating the key index  1225  by selecting and moving the symbol  1210 . Also,  FIG. 22  illustrates relocating the two aligned key indices  1305  and  1325  by selecting and moving the symbol  1310  that represent the two aligned key indices. 
     As mentioned above, some embodiments allow a user of a media editing application to select several key-indexed graphs in order to modify the selected graphs as one.  FIG. 23  illustrates an example of modifying the location of several overlapping key indices by selecting several graphs and moving a representation on the graph editor  1200 . In this example, the user has selected the opacity graph  1215  and position graph  2305 . As described above, the graphs  1215  and  2305  may be selected in any number of different ways. For instance, the user may select the graphs  1215  and  2305  through a cursor click operation while holding down a modifier key, by selecting user-interface controls (e.g., check boxes), through hotkeys (e.g., CTRL+A), etc. As shown in  FIG. 23 , after selecting the graphs, the user then moves a symbol  2310 . This movement causes the overlapping key indices  2315  and  2320  on only the selected graphs to be relocated; however, the movement does not affect key index on the scale graph  1220 . This also causes the symbols in the graph editor to change in some embodiments, as shown. Symbol  2310  indicated that there was a key index at its horizontal coordinate for all graphs in the graph editor. On the other hand, symbols  2330  and  2325 , after the key indices have been split up, indicate that there are multiple key indices at their horizontal coordinates, but not key indices for all of the graphs in the graph editor. Some embodiments use a third symbol in the graph editor at coordinates where there is only one key index. 
     The preceding section described and illustrated various ways to relocate key indices.  FIG. 24  illustrates a process  2400  of some embodiments for relocating one or more key indices. The process  2400  is performed by a media editing application in some embodiments. The process  2400  starts when it displays (at  2405 ) one or more key-indexed graphs with one or more key indices. Several examples of displaying such key-indexed graphs are illustrated in  FIGS. 17-23 . 
     The process  2400  then receives (at  2410 ) input to move one or more the key indices. In some embodiments, the input is received from a user interacting with a graphical user interface of the media editing application. Next, the process  2400  determines (at  2415 ) whether a key-indexed graph or a representation (like the symbol  1310  shown in  FIG. 17 ) on a graph editor is selected. 
     When a representation on the graph editor is selected, the process  2400  proceeds to  2455 ; otherwise it proceeds to  2420 . At  2455 , the process identifies the selected representation. After identifying the selected representation, the process  2400  identifies (at  2460 ) one or more key indices associated with the selected representation. Several examples of identifying key indices that are associated with a representation on a graph editor are described above by reference to  FIGS. 21-23 . 
     When the determination is made (at  2415 ) that the graph is selected, the process  2400  determines (at  2420 ) whether a representation of a key index (like the line  1315  shown in  FIG. 17 ) on a graph is selected. When such representation on the graph is selected, the process identifies (at  2425 ) the key index associated with the representation. 
     When the determination is made (at  2420 ) that a representation on the graph is not selected, the selected portion of the graph is an interior location on the graph. The process then identifies (at  2445 ) the selected interior location. Based on this identification, the process then identifies (at  2450 ) one or more key indices that are affected by the selected interior location. Several examples of identifying such key indices are described above by reference to  FIGS. 19-20 . For instance, some embodiments identify the first key indices on either side horizontally of the selected location. 
     Once or more key indices are identified, the process  2400  receives (at  2430 ) cursor movement. Based on the cursor movement, the process (at  2435 ) moves each identified key index to a new location on a corresponding graph. The process  2400  then awaits (at  2440 ) input to relocate more key index. When such input is received, the process returns to  2415 ; otherwise, the process ends. 
     One of ordinary skill in the art will realize that not all features for relocating key indices need to be used together. Accordingly, some embodiments perform variations on the process  2400 . For example, some embodiments might not allow the user to relocate one or more key indices by selecting and moving a representation (like the symbol  1310  shown in  FIG. 17 ) on a graph editor. Hence, in some such embodiments, the process  2400  may only include the operations for relocating a key index by manipulation a graph. Furthermore, in some embodiments the operations of process  2400  might be performed by two or more separate processes. That is, some embodiments could have one or more processes for relocating key indices through selection of the graph and a separate process for relocating key indices through selection within the graph editor. 
     D. Specifying Attribute Values 
       FIGS. 25-26  provide several illustrative examples of selecting a part of a graph directly and modifying the graph by moving the selected part to a new location. In particular, these figures illustrate (i) selectively modifying a graph without selecting any key index and (ii) selectively modifying the graph by selecting a key index on the graph. 
     As mentioned above, some embodiments allow a user to modify a graph without selecting any key index.  FIG. 25  illustrates an example of selectively modifying the opacity graph  1215  without selecting any key index. In this example, the user selects a part  2510  of the graph  1215  that is defined between the two key indices  1225  and  1305 . The selection of the interior location causes directional arrows  2505  to appear in the graph editing window  1240 . These arrows indicate that the selected part is selected and can be moved in two different directions. The user then modifies the graph  1215  by moving the selected part  2510  vertically. The selection and movement causes the opacity attribute across a portion of the graph starting from the key index  1225  and ending at the key index  1305  to be reduced by a constant value. 
       FIG. 25  also illustrates that the movement of the selected part  2505  of the graph  1215  modifies the slopes of several parts of the graph. For instance, the movement causes a part  1810  of the graph that is defined between a starting key index  1805  to have a negative slope. The movement also causes a part  2525  of the graph that is defined between the key index  1305  and an ending key index  2520  to have a positive slope. 
       FIG. 26  illustrates modifying a rotation graph  2610  by selecting a key index  2605  on the graph. Specifically, it illustrates selecting and moving the key index  2605  to specify attribute value at the key index. 
     In some embodiments, when a modification to a graph causes an attribute to fall below a predetermined threshold value, it also causes a shape that is defined by the graph to changes its form.  FIG. 26  illustrates an example of a shape  2615  that changes its form. The shape  2615  is defined by the rotation graph  2610 . In this example, when the movement of the key index  2605  on the graph  2610  causes the attribute value to fall below zero, it also causes the shape  2615  to appear inverted. In conjunction, or instead of it, some embodiments modify the color and/or pattern of the shape when the attribute value falls below a predetermined value. 
     Some embodiments use colors and/or patterns on shapes for various other reasons. One such reason is to distinguish graphs of different attributes. For instance, in some such embodiments, a first shape that is defined by an opacity graph may be displayed with one set of colors, while a second shape that defined by a scale graph may be displayed with another set of colors. Alternatively, or conjunctively, some embodiments use colors and/or patterns to distinguish one segment of the graph from another segment. For instance, when a graph includes multiple segments that define different parts of a shape, one part of the shape may be colored differently from another part in order to distinguish the two parts. 
     The preceding section described and illustrated various ways to modify attribute values at key indices.  FIG. 27  conceptually illustrates a process  2700  of some embodiments for setting attribute values at one or more key indices. The process  2700  is performed by a media editing application in some embodiments. The process  2700  starts when it displays (at  2705 ) one or more key-indexed graphs. Several examples of displaying such key-indexed graphs are illustrated in  FIGS. 25-26 . 
     The process  2700  then receives (at  2710 ) selection of a part of a key-indexed graph to set attribute values at one or more key indices. After receiving the selection, the process  2700  then determines (at  2715 ) whether the selected part of the key-indexed graph corresponds to a key index. Some embodiments make this determination based on comparing an input coordinate with a location of the key index on the graph. When the location corresponds to the key index, the process  2700  then identifies (at  2745 ) the corresponding key index. 
     When the selected part of the graph does not correspond to any key index, the process  2700  proceeds to  2720 . At  2720 , the process identifies key indices associated with the selected location. In some embodiments, the identification includes identifying the key indices that are adjacent to the selected part. That is, when the selection is at a point along the graph between two key indices, the process identifies the key indices on either side of the selected point. 
     Next, the process  2700  receives (at  2725 ) cursor movement. Based on the cursor movement, the process (at  2730 ) modifies the graph. The process  2700  then modifies (at  2735 ) attribute value at each identified key index in accordance with the modified graph. That is, as the graph is modified, the attribute values of the key indices are modified as well. Several examples of performing such modifications are described above by reference to  FIGS. 25-26 . The process also modifies (at  2740 ) the interpolation between key indices. For instance, in  FIG. 25 , the selection and movement of the part of the graph  1215  in between the key indices  1225  and  1305  causes the interpolation between the two key indices to be modified by a constant value. Similarly, modifying the attribute of one key index will modify the slope of a straight-line interpolation between the modified key index and a neighboring key index. 
     One of ordinary skill in the art will realize that not all features for setting attribute at key indices need to be used together. Accordingly, some embodiments perform variations on the process  2700 . For example, some embodiments might not allow the user to select and move a part of a graph that corresponds to a key index in order to set an attribute value at the key index. Hence, in some such embodiments, the process  2700  might only include the operations for setting attribute values by selecting and moving a part of the graph that does not correspond to any key index. Furthermore, in some embodiments the operations of process  2700  might be performed by two or more separate processes. That is, some embodiments could have one process for modifying attribute values at key indices through selection of the graph between two key indices and a separate process for modifying attribute values at key indices through selection of the graph at a key index. 
     E. Creating a Curve on a Graph 
       FIGS. 28-35  illustrate examples of forming a curve on a straight line graph by interacting with a shape that is defined by the line graph. Specifically, these figures illustrate (i) selecting an interior location of the shape, (ii) moving the interior location vertically to form the curve on the line graph, and (iii) moving the interior location horizontally to form the curve. In some embodiments, the curve is a parameterizable curve (e.g., a bezier curve, a b-spline curve). 
       FIG. 28  illustrates an example of receiving selection of an interior location  2825  within a shape  2815  that is defined a line graph  2820 . In particular, this figure illustrates receiving the selection of the interior location  2825  in order to create a curve on the line graph  2820 . A location within a shape may be selected in a number of different ways. For example, the location may be selected by a user holding down a button of cursor controller along with a modifier key, holding down a right button of the cursor controller, etc. As shown in  FIG. 28 , when a user selects the interior location  2825 , the user is presented with a directional arrows  2805  that indicate that the interior location is selected and can be moved in a number of different directions (e.g., vertically, horizontally, diagonally). 
       FIG. 29  provides an illustrative example of forming the curve on the graph by moving the selected location vertically. As shown, when the selected interior location  2825  is moved vertically (e.g., through a drag operation), the directional arrows  2805  is replaced by a directional arrow  2905  that indicates that the selected location is being moved. The movement also causes the curve to be modified on the graph  2820 . 
     In some embodiments, a user&#39;s selection and movement of an interior location creates a smooth curve by pushing out one part of the line graph while pulling in another part of the line graph. For instance, in the example illustrated in  FIG. 29 , the selection and downward movement of the interior location creates the curve by pushing out one part of the graph  2820  to the left of the selected interior location outwards while pushing in another part to the right of the selected interior location inwards. In some such embodiments, the cursor selection and movement of the interior location creates the curve on the graph by defining a local inflection point on a line graph at the coordinate that corresponds to the selected location. For instance, in  FIG. 29 , the downward movement of the cursor defines a local inflection point on the line graph  2820  at the x-coordinate of the selected location  2825 . 
     In the examples given above and the many examples illustrated below, the selection and movement of an interior location within a shape modifies a graph (e.g., creates a curve on the graph) and does not result in the relocation of one or more key indices. This is different from the example operations described above by reference to  FIGS. 19 and 20 . Some embodiments enable both these functionalities by providing user interface tools, user interface techniques, and/or shortcuts (e.g., through the use of hotkeys) to differentiate the two functionalities. Other embodiments do not allow both these functionalities but instead allow only one or the other. Still other embodiments provide both these functionalities but provide one functionality for one type of graph (e.g., audio level graph) and another functionality for another type of graph (e.g., position graph). Furthermore, some embodiments provide different functionalities in different types of windows, and/or provide one functionality in a first type of view (e.g., interpolation mode, full view), and another functionality in a second type of view (e.g., summary mode, collapsed view). 
       FIG. 30  illustrates an example of forming a curve on the graph by moving an interior location  3005  horizontally. In this example, the user selects an interior location near the key index  3010 . The user then moves the interior location  3005  to form a curve on the straight line graph  2820 . In some embodiments, the selection and movement of an interior location causes a concave curve to be formed on a graph. For instance, in the example illustrated in  FIG. 30 , the selection and movement of the interior location creates the concave curve by pulling the straight line graph  2820  inwards in the direction that corresponds to the cursor movement. Correspondingly,  FIG. 31  illustrates an example in which the selection and movement of an interior location  3105  causes a convex curve to be formed. As shown, selecting an interior location and moving the cursor towards a straight line graph causes the curve to be pushed outwards, away from the selection point, in some embodiments. 
     In some embodiments, the selection and movement of an interior location modifies tangents at key indices. In some embodiments, the interpolation between the key indices is a parameterizable curve that is defined by the tangents. The parameterizable curve is a bezier spline in some embodiments.  FIGS. 32-33  illustrate several examples of modifying the angle of the tangents at key indices  3205  and  3210 . In these examples, a segment  3215  of the graph is defined by the two key indices  3205  and  3210  and the tangents at the two key indices. Also, for illustrative purposes, two dashed lines  3220  and  3225  that represent the tangents are shown. 
       FIG. 32  illustrates an example of modifying the angle of the tangents at the key indices by selecting and moving an interior location upwards towards a segment of the line graph. As shown, when the interior location  3230  is selected, the tangents at the two key indices  3205  and  3210  are initially parallel to one another. However, the upward movement affects the tangents  3220  and  3225  at the key indices  3205  and  3210 . Specifically, in this example, the upward movement causes the tangent  3220  at the key index  3205  to move downwards while at the same time causing the tangent  3225  at the key index  3210  to move upwards. 
       FIG. 33  illustrates an example of the affecting the angle of the tangents at the key indices by selecting and moving the interior location  3230  downwards away from the segment of the line graph. Specifically, this figure illustrates that the downward movement of selected interior location causes the tangent  3220  at the key index  3205  to move upwards while at the same time causing the tangent  3225  at the key index  3210  to move downwards. 
     In  FIGS. 32 and 33 , the selected internal location is horizontally halfway in between the two key indices and the angles of the tangents  3220  and  3225  are modified equally. In some embodiments, the amount of modification to the angle of the tangent is weighted depending on the location of the internal selection point. For instance, if the selection point is closer to a first key index than a second key index, the tangent at the first key index will be modified by a greater amount than at the second key index. In some embodiments, the angle modification is weighted such that the inflection point of the curve between the two key indices is at the horizontal coordinate of the selection location. 
     In conjunction with affecting the angle of the tangents, or instead of it, in some embodiments, the selection and movement of an interior location affects the length of the tangents at key indices. In some such embodiments, the lengths of tangents at the key indices are weighted such that the movement causes the length of one tangent to become shorter while causing the length of another tangent to become longer. 
       FIGS. 34-35  illustrate several examples of the affecting the lengths of tangents at the key indices by selecting and moving an interior location  3405  horizontally. Specifically,  FIG. 34  illustrates that the selection and horizontal movement of the selected interior location  3405  away from the segment  3215  causes the tangent  3220  at the key index  3205  to become shorter while causing the tangent  3225  at the key index  3210  to become longer. Similarly,  FIG. 35  illustrates that the selection and horizontal movement of the selected interior location towards the segment  3215  causes the tangent  3220  at the key index  3205  to become longer while causing the tangent  3225  at the key index  3210  to become shorter. 
     As shown, in some embodiments, moving the cursor horizontally towards a first key index and away from a second key index shortens the tangent at the first key index and lengthens the tangent at the second key index. In some cases, as in the examples, this causes the inflection point of the curve to move with the cursor towards the first key index. This is because, in some embodiments, the length of a tangent at a key index defines the sharpness of the curve moving away from the key index—the shorter the tangent, the sharper the curve. 
     In the examples of  FIGS. 34 and 35 , the selection point is vertically halfway between the two key indices. In some embodiments, the amount of modification to the length of the tangents is weighted based on the internal selection point. That is, if the selection point is closer to a first key index than a second key index, the tangent at the first key index will be modified more than the tangent at the second key index. 
     The above examples illustrate the definition of a parameterizable curve based on control points that are on the curve (the key indices) and tangents at the control points. One example of such a parameterizable curve is a bezier spline. Some embodiments use parameterizable curves defined by (i) control points not on the curve and (ii) a control polygon. One example of such a parameterizable curve is a b-spline. One of ordinary skill in the art will recognize that interpolations between key indices may use other parameterizable curves. 
     Some embodiments allow a curve between two key indices to be formed freely. For instance, in some such embodiments, the user can grab a region within an area of a key-indexed graph and push or pull the region in any way to freely form the curve between the two key indices. Alternative, or conjunctively, some embodiments constrain the movement that the user can make. Such constraint puts a limit on the movement to provide for a more precise interpolation between the two key indices. 
     The preceding section described various examples of creating a curve on a graph by selecting and moving an interior location within a shape that is defined by the graph.  FIG. 36  illustrates a process  3600  of some embodiments for creating a curve on a graph by selecting and moving an interior location within a shape that is defined by the graph. Process  3600  is performed by a media editing application in some embodiments. The process  3600  starts at when it displays (at  3605 ) a key-indexed graph. Several examples of displaying such key-indexed graphs are illustrated in  FIGS. 28-35 . 
     The process  3600  then receives (at  3610 ) selection of an interior location within a shape defined by the key-indexed graph to create the curve on the graph. For instance, as noted above, the selection could be a mouse click combined with a key combination, or a right click. Next, the process receives (at  3615 ) movement of the selected interior location. For instance, when the input includes a mouse click, the movement is movement of the mouse in some embodiments. The process then identifies (at  3620 ) the direction of this movement of the selected interior location. For instance, the process identifies whether the movement is left, right, up, down, or diagonal. One example of such selection and movement of an interior location is described above by reference to  FIG. 28 . 
     Next, process  3600  creates (at  3625 ) a curve on the graph in accordance with the cursor movement and selected location. Several examples of creating such curves are described above by reference to  FIGS. 28-35 . In some embodiments, the curve is a parameterizable curve (e.g., a bezier spline) defined by the key indices and tangents at the key indices. In conjunction with forming the curve on the graph, the process computes the interpolation between key indices (e.g., by applying bezier mathematics when the curve is a bezier spline, or similar computations for other parameterizable curves). The process also (at  3635 ) modifies the attribute values between the key indices. 
     One of ordinary skill in the art will realize that not all features for creating parameterizable curves between key indices need to be used together. Accordingly, some embodiments perform variations on the process  2700 . For example, in some embodiments the operations of process  2700  might be performed by two or more separate processes. That is, some embodiments could have one process for horizontal movement and a separate process for vertical movement. 
     F. Modifying a Section of a Graph Independently of Neighboring Section 
       FIGS. 37-39  illustrate examples of selecting and modifying a section of a graph independently of other neighboring sections. In particular, these figures illustrate (i) receiving selection of the section for independent modification, (ii) moving the section to separate it from the other neighboring sections, and (iii) moving the section to realign it with the other neighboring sections. In these examples, a section  3705  of a graph  3745  is initially defined by key indices  3735  and  3730 . Also, a region  3720  of a shape  377  is defined by the section  3705 . 
       FIG. 37  illustrates an example of receiving selection of the section  3705  for independent modification. In this example, the cursor selection (e.g., a cursor click operation such as a contextual click within) of a part  3710  of the section causes directional arrows  3715  to appear in a graph editing window  3740 . These arrows indicate that the section  3705  is selected and can be moved in two different directions. Alternative, or conjunctively, some embodiments change the appearance (e.g., color, pattern) of a region of a shape that is associated with a section of a graph. For instance, in  FIG. 37 , the cursor selection of the part  3710  of the section causes the region  3720  to change its color. Specifically, the cursor selection causes the region  3720  to change its color so that the region appears distinct from other neighboring regions  3725  and  3730  of the shape. 
       FIG. 38  illustrates moving the section  3705  vertically to separate the section from other neighboring sections of the graph. Specifically, this figure illustrates separating the section  3705  from sections  3805  and  3810 . As shown, the movement of the part  3710  of the section causes the section  3705  to be broken apart from the sections  3805  and  3810 . As the section  3705  defines the region  3720 , the vertical movement also causes the region  3720  to be resized. However, the movement does not affect the other sections ( 3805  and  3810 ) and the other regions ( 3725  and  3730 ) that are defined by these other sections. 
     To facilitate such independent modification, some embodiments automatically create one or more new key indices when a section is split away from another section. For instance, in  FIG. 38 , as a result of the movement, the section  3705  is defined by two new key indices  3815  and  3820 , and is no longer defined by the key indices  3735  and  3730 . 
     Allowing a section of a graph to be modified independently of another section is particularly useful in creating a sudden transition in an attribute between two key indices. For instance, in  FIG. 38 , if the graph  3745  represents a brightness attribute of a video clip, then the brightness value at the key index  3735  will suddenly rise to about double at the following key index  3815 . Also, the brightness at the key index  3820  will suddenly fall to about half at the following key index  3730 . In some embodiments, when a section of a graph is separated, a new key index is created one key index away from an existing key index. In other words, if the key index represents a sample of audio, then the new key index might represent the next or previous sample of audio. Similarly, if the key index represents a frame of video, then the new key index might represent the next or preview frame of video. 
       FIG. 39  illustrates realigning the section  3705  with the sections  3805  and  3810 . Specifically, it illustrates realigning these sections ( 3705 ,  3805 , and  3810 ) by moving the part  3710  of the section downwards. When the movement causes a section of a graph to be realigned with another section, some embodiments modify the appearance (e.g., color, pattern) of a region of a shape that is defined by the section. For instance, in  FIG. 39 , when the section  3705  is realigned with the neighboring sections  3805  and  3810 , the region  3720  changes its color to indicate that the sections are realigned. Specifically, in this example, the movement causes the region  3720  to revert back to its original color (i.e., one that matches the regions  3725  and  3730 ). Alternatively, or conjunctively, some embodiments provide a snapping function for aligning two or more sections of a key-indexed graph that are not aligned. In some such embodiments, the snapping function causes a first vertex of one section that is next to or near a second vertex of another section to snap together. 
     When a section is realigned with another section, some embodiments maintain the new key indices that were created as a result of the separation. Alternatively, the new key indices may also be automatically deleted. For instance, in  FIG. 39 , the key indices  3815  and  3820  are automatically deleted when the section  3705  is realigned with the sections  3805  and  3810 . 
     The preceding section described various examples of selecting and modifying a section of graph independently of another section.  FIG. 40  illustrates a process  4000  of some embodiments for selecting and modifying a section of a graph independently of a neighboring section. Process  4000  is performed by a media editing application in some embodiments. The process  4000  starts at  4005  when it displays a key-indexed graph. Several examples of displaying such key-indexed graph are illustrated in  FIGS. 37-39 . 
     The process  4000  then receives (at  4010 ) a selection of a section of key-indexed graph. In some embodiments, the section is a portion of the graph between two key indices. One example of receiving such a selection is illustrated in  FIG. 37 . The process then modifies (at  4015 ) appearance of the section of the graph. As mentioned above, some embodiments accomplish this by changing the color/and or pattern of a region of a shape that is defined by the selected section. 
     The process  4000  then receives (at  4020 ) movement of the selected section of the graph. For instance, the process receives input from a cursor controller to move the selected section up or down. An example of receiving movement of such a selected section is described above by reference to  FIG. 38 . The process then determines (at  4025 ) whether the movement caused the section to be separated from another neighboring section. When the section is separated, the process proceeds to  4035 ; otherwise, it proceeds to  4030 . 
     When the determination is made that the movement separated the selected section from the neighboring section, the process  4000  automatically creates (at  4035 ) one or more new key indices. That is, at the boundaries between sections, there are two key indices (one for each section) instead of one key index. An example of such automatic creation is described above by reference to  FIG. 38 . Once the new key indices are created, the process  4000  then sets (at  4040 ) the attribute values at the new key indices. In some embodiments, the new key index is assigned the value that its bordering key index had prior to the creation of the new key index. 
     The process  4000  determines whether the movement caused the section to be aligned with another section. When the determination is made that the section is aligned with another section, the process then modifies the appearance of the graph. An example of such modification is described above by reference to  FIG. 39 . 
     Some embodiments perform variations on the process  4000 . For example, some embodiments might not change the appearance of a graph or shape. Hence, in some such embodiments, the process  4000  might not include the appearance changing operations and only include several other operations. Furthermore, in some embodiments the operations of process  4000  might be performed by two or more separate processes. That is, some embodiments could have one process for separating a section and a separate process for re-aligning sections. 
     III. Overall Software Architecture 
     A. Software Architecture of an Application 
     In some embodiments, the above-described operations and user-interface tools are implemented as software running on a particular machine, such as a desktop computer, laptop, or handheld device, (or stored in a computer readable medium).  FIG. 41  conceptually illustrates the software architecture of an application  4100  in accordance with some embodiments. In some embodiments, the application is a stand-alone application or is integrated into another application (for instance, application  4100  might be a portion of a media editing 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 (e.g., web-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 client machine remote from the server (e.g., via a browser on the client machine). 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. In still other embodiments, the components (e.g., engines, modules) illustrated in  FIG. 41  are split among multiple applications. For instance, in some embodiments, one application defines one or more key-indexed graphs to use in creating the media presentation, while another application performs composing and rendering of the media presentation based on the key-indexed graphs. 
     As shown in  FIG. 41 , the application  4100  includes a graphical user interface  4105 , graph editing module  4115 , interpolation module  4125 , preview generator  4135 , and rendering engine  4155 . The graphical user interface  4105  provides user-interface tools (e.g., display areas, user-interface controls, user-selectable graph elements, etc.) that a user of the media editing application  4100  interacts with in order to create a media presentation. In some embodiments, the graphical user interface includes a graph display area  4110  that displays one or more key-indexed graphs that can be modified by the user according to one or more of the novel graph-editing operations described above. 
     When the graph display area  4110  displays a key-indexed graph, some embodiments provide graph-selection and shape-selection capability by defining the key-indexed graph and its associated shape as selectable and modifiable elements (i.e., as items that can be selected and modified by the user). 
     As shown in  FIG. 41 , to facilitate graph editing and displaying operations, the media editing application  4100  includes the graph editing module  4115 . In some embodiments, when the user inputs instructions to modify a particular key-indexed graph through one of the user-interface tools, the graph editing module  4115  receives and processes these instructions in order to modify and redraw the key-indexed graph in the graphical user interface  4105 . As shown in  FIG. 41 , the graph editing module  4115  in some embodiments includes a graph drawer  4120  for drawing and/or redrawing one or more of the key-indexed graphs in the graphical user interface  4105 . 
     To draw the key-indexed graphs, the graph drawer  4120  in some embodiments receives attributes values from the interpolation module  4125 . This interpolation module  4125  in some embodiments is a module in the media editing application  4100  that receives the user modifications to one or more of the key-indexed graphs (e.g., attribute values at key indices, interpolation between the key indices) and performs data interpolation. For instance, in some such embodiments, the interpolation module receives a first attribute value at one key index and a second attribute value at a subsequent key index and fills in (i.e., interpolates) the attribute values between the two key indices in accordance with the interpolation that is defined between the two key indices. In some embodiments, the interpolation module performs the interpolation based on parameterizable curve mathematics in accordance with the angle of the tangents at the key indices and/or the length of the tangents at the key indices. 
     Preview generator  4135  in some embodiments generates a preview (e.g., real-time preview) of the media presentation that is being created by the media editing application  4100 . When the preview generates the preview, it generates the preview by incorporating the media clip into the preview with the attribute values defined by one or more of the key-indexed graph in some embodiments. 
     As shown in  FIG. 41 , the preview generator  4135  of some embodiments includes a preview processor  4145  that may be used to communicate with the graph editing module  4115 , and send and receive data (e.g., project data) to and from the graphical user interface  4105  and/or the set of data storages  4170 . In addition, the preview processor  4145  may send and receive data to and from a section identifier  4140  and/or a fetcher  4150 . In some embodiments, the preview processor  4145  sends timeline data to the section identifier  4140  that generates an appropriate set of data (e.g., a segment table) needed to generate the preview. In some embodiments, the preview processor  4145  supplies the set of data generated by the section identifier  4140  to the fetcher  4150 . The fetcher  4150  of some embodiments retrieves content data (e.g., video frame data, audio sample data) from the set of data storages  4170  based on the set of data provided by the preview processor  4145 . The preview generator  4135  in some embodiments receives and uses the content data in order to generate the preview. 
     Rendering engine  4155  enables the storage or output of audio and video from the media editing application  4100 . For example, the rendering engine  4155  may use attribute values associated with one or more attribute of a media clip to render the media clip for display and/or storage. In some embodiments, the rendering engine  4155  may receive attribute data from the preview generator  4135  in order to generate the preview. In some embodiments, data from the rendering engine  4155  (e.g., audio and video data of a video scene, preview data, etc.) is passed to the graphical user interface  4105  and/or an audio playback module  4185 . 
     The operating system  4195  of some embodiments includes a cursor controller driver  4175  for allowing the application  4100  to receive data from a cursor control device, a keyboard driver  4180  for allowing the application to receive data from a keyboard, the audio playback module  4185  for processing audio data that will be supplied to an audio device (e.g., a soundcard and speakers), and a display module  4195  for processing video data that will be supplied to a display device (e.g., a monitor). 
     An example operation of the media editing application  4100  will now be described by reference to the components (e.g., engines, modules) illustrated in  FIG. 41 . A user interacts with user-interface tools (e.g., graphs, shapes defined by the graphs, user-selectable controls, display areas) in the graphical user interface  4105  of the media editing application via input devices such as a cursor controller (e.g., a mouse, touchpad, touch screen, etc.) and keyboard (e.g., physical keyboard, virtual keyboard). 
     When the user interacts with one or more user-selectable elements of key-indexed graphs and/or other graph modifying items (e.g., controls, menu items) in the graphical user interface  4105 , some embodiments translate the user interaction into input data and send this data to the graph editing module  4115 . As mentioned above, the graph editing module  4115  in some embodiments receives the input data and processes the input data in order to modify one or more of the key-indexed graphs. For example, when the graph module receives instructions for creating a key index on a key-index graph that is associated with an attribute of a media clip, the graph editing module  4115  processes the input data (e.g., by identifying the location and attribute value) and creates the key index. 
     When the user input result in a need to modify the interpolation between two or more key indices in a particular key-indexed graph, the editing module  4115  sends the input data to the interpolation module. The interpolation module  4125  receives the input data (e.g., attribute value at key indices, interpolation between the key indices) from the editing module  4115  and performs data interpolation. For instance, in some such embodiments, the interpolation module receives a first attribute value at one key index and a second attribute value at a subsequent key index and fills in (i.e., interpolates) the attribute values between the two key indices in accordance with the interpolation that is defined between the two key indices (e.g., straight line, parameterizable curve, etc.). In some embodiments, the editing modules  4115  receive the attribute values (i.e., graph data) from the interpolation module  4155  and stores the attribute values in memory (e.g., the set of storage  4170 ). The graph drawer in some embodiments uses these attribute values to generate a display of the particular key-index graph. 
     In some embodiments, the attribute values that are stored in memory are used by preview generator  4135  in order to generate a preview of the media presentation. As mentioned above, the rendering engine may work in conjunction with the preview generator in order to render the preview for display and/or storage. Alternatively, the rendering engine may work separately from the preview generator in order to render the media presentation for display and/or storage. 
     B. Data Structure of a Key-Indexed Graph 
     When a key-indexed graph is displayed in a display area of a graphical user interface (UI), some embodiments provide graph-selection and shape-selection capability by defining the key-indexed graph and its associated shape as selectable and modifiable items in the UI of the media editing application (i.e., as items that can be selected and modified by the user in the UI). 
       FIG. 42  conceptually illustrates a data structure of a key-indexed graph  4200  of some embodiments that may be displayed in the display area (like the graph display area  4110 ). In this data structure diagram, the root node represents the key-index graph  4200 , while the leaf nodes represent selectable items in the UI. As shown, the key-index graph  4200  includes several segments  4205 - 4215 . Each graph segment includes (i) two key indices that represent the endpoints of the segment, (ii) a user-selectable line segment that represent the segment between the two key indices, and (iii) a user-selectable shape that is defined by the graph segment. For instance, graph segment  1   4205  includes key indices  4275  and  4220  as endpoints, user-selectable line segment  4230  as the segment between the key indices, and a user-selectable shape  1   4280  as the shape. 
     As shown in  FIG. 42 , each of the key indices  4275  and  4220  includes two child nodes that represent user-selectable items in the UI. For instance, the key index  1   4275  includes a user-selectable key index  1   4240  at the key index  1  on the line graph and a user-selectable representation  1   4255  (e.g., the representation in the shape). As mentioned above by reference to  FIG. 26 , some embodiments allow a user to modify a key-indexed graph by selecting and moving a particular user-selectable key index on the graph, such as the user-selectable key index  1   4240 . Instead of, or in conjunction with the particular user-selectable key index, some embodiments provide a user-selectable representation (like the user-selectable representation  1   4255 ) for modifying a key index on a key-index graph. Such user-selectable representation is described above by reference to  FIG. 17 . 
     In some embodiments, a graph segment defines a shape as a selectable element in the UI. For instance, in  FIG. 42 , the graph segment  1   4205  defines the user-selectable shape  1   4280 , while the graph segment  2   4210  defines a user-selectable shape  2   4270 . The user-selectable shape in some embodiments can be selected and manipulated by a user in order to (i) create and modify a curve on a graph segment of a key-indexed graph, and/or (ii) relocate key indices on the key index graph. Several examples of creating the curve by manipulating such user-selectable shape are described above by reference to  FIGS. 28-35 . Furthermore, several examples of relocating one or more key indices by manipulating such user-selectable inner area are described above by reference to  FIGS. 19-20 . 
     In conjunction with the user-selectable shape, or instead of it, a graph segment may include a user-selectable segment between two key indices. For instance, in  FIG. 42 , the graph segment  1  includes the user-selectable line segment  1   4230 , while the graph segment  2   4210  includes a user-selectable line segment  2   4235 . As mentioned above by reference to  FIG. 25 , such user-selectable line segments in some embodiments allows the user to selectively modify a key-indexed graph without actually selecting any key index. 
     In a display of a UI, several graph segments of a key index-graph may be adjoined by a common key index. For instance, in  FIG. 42 , the graph segments  1  and  2  ( 4205  and  4210 ) share a common key index (i.e., the key index  2   4220 ). As a result of sharing one key index, the graph segments  1  and  2  ( 4205  and  4210 ) share the user-selectable index  2   4245  and a user-selectable representation  2   4260 . Accordingly, when one of the user-selectable representations ( 4245  and  4260 ) is selected and moved, it causes both the graph segment ( 4205  and  4210 ) to be modified. One example of modifying the slopes of two graph segments of a key-indexed graph by selecting and moving a user-selectable key-index (like the user-selectable key index  2   4245 ) is illustrated in  FIG. 26 . Furthermore, an example of modifying the length of the graph segments by selecting and moving a user-selectable representation (like the user-selectable representation  2   4260 ) is described above by reference to  FIG. 18 . 
     In some cases, when two graph segments share one common key index, a selection and movement of a user-selectable shape (like the user selectable shape  1   4280 ) of the first graph segment may affect the second graph segment. For instance, a selection and movement of an interior location to relocate one or more key indices may affect the lengths of each of the two segments. Several examples of affecting the lengths of two segments by selecting and moving an interior is described above by reference to  FIGS. 19-20 . 
     Furthermore, when two graph segments share one common key index, a selection and movement of a user-selectable line segment (like the user-selectable line segment  1   4230 ) of the first graph segment may affect the second graph segment. For instance, a selection and movement of the user-selectable line segment of the first graph segment may affect the slope of the second graph segment because the shared key index will be moved. An example of modifying the slope of one segment by moving an adjacent segment is described above by reference to  FIG. 25 . 
     The key-indexed graph  4200  in  FIG. 42  was described above to include certain features. However, one of ordinary skill will realize that not all these features need to be used together. For instance, some embodiments might allow an interior location of a shape to be selected in order to create key indices but might not allow it to be manipulated in order to create a curve. Similarly, some embodiment might allow a key-indexed graph to be selected and moved anywhere along its duration but might not allow a representation of a key index (e.g., line) to be selected and moved. 
     C. Process for Defining an Application 
     The section above described and illustrated the software architecture of an application in accordance with some embodiments.  FIG. 43  conceptually illustrates a process  4300  of some embodiments for defining an application, such as application  4100 . As shown, process  4300  begins by defining (at  4305 ) or more key-indexed graph objects. In some embodiments, the key-indexed graph object includes attributes (e.g., color of a shape, thickness of a graph line) and/or methods that perform a particular function (e.g., change color of the shape, modify the graph line). 
     Process  4300  then defines (at  4310 ) a graph editing interface. The graph display area  4110  is an example of such a module. Next, the process defines (at  4315 ) a graph editing module. As mentioned above, the graph editing module, in some embodiments, receives the instructions from the media editing module and processes the instructions to modify one or more of key-indexed graphs. 
     The process next defines (at  4320 ) an interpolation module. The interpolation module  4125  is an example of such a module. Process  4300  next defines (at  4325 ) other media editing tools and functionalities. After  4325 , the application is defined. Accordingly, at  4330 , the process  4300  stores a representation of the application in a readable storage medium. The readable storage medium may be a disk (e.g., CD, DVD, hard disk, etc.) or a solid-state storage device (e.g., flash memory) in some embodiments. One of ordinary skill in the art will recognize that the various modules and UI items defined by process  4300  are not exhaustive of the modules and UI items that could be defined and stored on a computer readable storage medium for an editing application incorporating some embodiments of the invention. 
     IV. Computer System 
     Many of the above-described processes, modules, and interfaces 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”, “readable storage medium”, or “machine readable medium”). When these instructions are executed by one or more computational element(s) (such as processors or other computational elements like ASICs and FPGAs), they cause the computational element(s) to perform the actions indicated in the instructions. Computer is meant in its broadest sense, and can include any electronic device with a processor. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, RAM chips, hard drives, EPROMs, 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 in its broadest sense. It can 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 computer systems define one or more specific machine implementations that execute and perform the operations of the software programs. 
       FIG. 44  conceptually illustrates a computer system  4400  with which some embodiments of the invention are implemented. For example, the system described above in reference to  FIG. 41  may be at least partially implemented using sets of instructions that are run on the computer system  4400 . As another example, the processes described in reference to  FIGS. 10 ,  16 ,  24 ,  27 ,  36 , and  40  may be at least partially implemented using sets of instructions that are run on the computer system  4400 . 
     Computer system  4400  includes a bus  4410 , a processor  4420 , a system memory  4430 , a read-only memory (ROM)  4440 , a permanent storage device  4450 , a graphics processing unit (“GPU”)  4460 , input devices  4470 , output devices  4480 , and a network connection  4490 . The components of the computer system  4400  are electronic devices that automatically perform operations based on digital and/or analog input signals. The various examples of user interfaces shown in  FIGS. 8 ,  37 ,  14 ,  26 ,  28 ,  37 , and  41  may be at least partially implemented using sets of instructions that are run on the computer system  4400  and displayed using the output devices  4480 . 
     One of ordinary skill in the art will recognize that the computer system  4400  may be embodied in other specific forms without deviating from the spirit of the invention. For instance, the computer system may be implemented using various specific devices either alone or in combination. For example, a local PC may include the input devices  4470  and output devices  4480 , while a remote PC may include the other devices  4410 - 4460 , with the local PC connected to the remote PC through a network that the local PC accesses through its network connection  4490  (where the remote PC is also connected to the network through a network connection). 
     The bus  4410  collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the computer system  4400 . For instance, the bus  4410  communicatively connects the processor  4420  with the system memory  4430 , the ROM  4440 , and the permanent storage device  4450 . From these various memory units, the processor  4420  retrieves instructions to execute and data to process in order to execute the processes of the invention. In some embodiments, the processor comprises a Field Programmable Gate Array (FPGA), an ASIC, or various other electronic components for executing instructions. In some cases, the bus  4410  may include wireless and/or optical communication pathways in addition to or in place of wired connections. For example, the input devices  4470  and/or output devices  4480  may be coupled to the system  4400  using a wireless local area network (W-LAN) connection, Bluetooth®, or some other wireless connection protocol or system. 
     The ROM  4440  stores static data and instructions that are needed by the processor  4420  and other modules of the computer system. The permanent storage device  4450 , 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 computer system  4400  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  4450 . 
     Other embodiments use a removable storage device (such as a floppy disk, flash drive, or CD-ROM) as the permanent storage device. Like the permanent storage device  4450 , the system memory  4430  is a read-and-write memory device. However, unlike storage device  4450 , the system memory  4430  is a volatile read-and-write memory, such as a random access memory (RAM). The system memory stores some of the instructions and data that the processor needs at runtime. In some embodiments, the sets of instructions used to implement the invention&#39;s processes are stored in the system memory  4430 , the permanent storage device  4450 , and/or the read-only memory  4440 . For example, the various memory units include instructions for processing multimedia items in accordance with some embodiments. From these various memory units, the processor  4410  retrieves instructions to execute and data to process in order to execute the processes of some embodiments. 
     In addition, the bus  4410  connects to the GPU  4460 . The GPU of some embodiments performs various graphics processing functions. These functions may include display functions, rendering, compositing, and/or other functions related to the processing or display of graphical data. 
     The bus  4410  also connects to the input devices  4470  and output devices  4480 . The input devices  4470  enable the user to communicate information and select commands to the computer system. The input devices include alphanumeric keyboards and pointing devices (also called “cursor control devices”). The input devices also include audio input devices (e.g., microphones, MIDI musical instruments, etc.) and video input devices (e.g., video cameras, still cameras, optical scanning devices, etc.). The output devices  4480  include printers, electronic display devices that display still or moving images, and electronic audio devices that play audio generated by the computer system. For instance, these display devices may display a GUI. The display devices include devices such as cathode ray tubes (“CRT”), liquid crystal displays (“LCD”), plasma display panels (“PDP”), surface-conduction electron-emitter displays (alternatively referred to as a “surface electron display” or “SED”), etc. The audio devices include a PC&#39;s sound card and speakers, a speaker on a cellular phone, a Bluetooth® earpiece, etc. Some or all of these output devices may be wirelessly or optically connected to the computer system. 
     Finally, as shown in  FIG. 44 , bus  4410  also couples computer  4400  to a network  4490  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”), an Intranet, or a network of networks, such as the Internet. For example, the computer  4400  may be coupled to a web server (network  4490 ) so that a web browser executing on the computer  4400  can interact with the web server as a user interacts with a GUI that operates in the web browser. 
     As mentioned above, the computer system  4400  may include electronic components, such as microprocessors, storage and memory that store computer program instructions in one or more of a variety of different computer-readable media (alternatively referred to as computer-readable storage media, machine-readable media, machine-readable storage media, 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, ZIP® disks, 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 processor and includes sets of instructions for performing various operations. Examples of hardware devices configured to store and execute sets of instructions include, but are not limited to application specific integrated circuits (ASICs), field programmable gate arrays (FPGA), programmable logic devices (PLDs), ROM, and RAM devices. Examples of computer programs or computer code include machine code, such as 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. 
     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” and “computer readable media” 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. It should be recognized by one of ordinary skill in the art that any or all of the components of computer system  4400  may be used in conjunction with the invention. Moreover, one of ordinary skill in the art will appreciate that any other system configuration may also be used in conjunction with the invention or components of the invention. 
     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 describes the use of a cursor in the graphical user interface to control (e.g., select, move) user-interface elements in the graphical user interface. However, in some embodiments, these user-interface elements in the graphical user interface can also be controlled or manipulated through other control, 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 user-interface elements 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 user-selectable element in the graphical user interface by simply touching that particular user-selectable element 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 a user-selectable element 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. 
     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 (i.e., different embodiments may implement or perform different operations) without departing from the spirit of the invention. One of ordinary skill in the art would also recognize that some embodiments may divide a particular module into multiple modules. In addition, although the examples given above may discuss accessing the system using a particular device (e.g., a PC), one of ordinary skill will recognize that a user could access the system using alternative devices (e.g., a cellular phone, PDA, smartphone, BlackBerry®, or other device). 
     One of ordinary skill in the art will realize that, while the invention has been described with reference to numerous specific details, the invention can be embodied in other specific forms without departing from the spirit of the invention. For instance, alternate embodiments may be implemented by using a generic processor to implement the video processing functions instead of using a GPU. 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: 20090430
Publication Date: 20131022
Grant Date: 20131022
Priority Date: 20090430
Inventors: LANGMACHER TOM
LIBERTO, III SAMUEL JOSEPH
Assignee: APPLE INC
CPC Classifications: [{"code": "G11B27/034", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04845", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B27/34", "inventive": true, "first": true, "tree": "[]"}, {"code": "G11B27/34", "inventive": true, "first": true, "tree": "[]"}, {"code": "G11B27/034", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04845", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 43031325