Patent Publication Number: US-9852768-B1

Title: Video editing using mobile terminal and remote computer

Description:
BACKGROUND 
     Field 
     The present disclosure relates to video editing. More specifically, the present disclosure relates to video editing using a mobile terminal and at least one remote computer. 
     Discussion of Related Technology 
     People use smartphones to take and edit videos. Simple video editing like trimming can be done on smartphones. Smartphones may not have processing power or functions of more complex video editing like superimposing visual objects. More complex editing is typically performed using desktop computers or specialized systems. 
     SUMMARY 
     One aspect of the invention provides a method of video editing. The method comprises: providing a video editing mobile application on a mobile terminal, wherein the video editing mobile application does not have the capability of video editing to overlay a user selected visual effect video clip over a user selected user video for generating a single resulting video while the video editing mobile application offers video editing of adding the user selected visual effect video clip to the user selected user video by computing power of one or more remote computers, wherein the video editing mobile application comprises alpha-format still images corresponding to each of a plurality of visual effects offered therein; receiving a user command for selecting a first user video for editing; receiving at least one user command for adding a first one of the plurality of visual effects to the user selected first user video, wherein adding involves selecting the first visual effect, and selecting a first time window for adding the first visual effect within a time span of the first user video; providing a preview displaying a series of alpha-format still images over the first user video to emulate the first visual effect over the first user video without generating a single video clip in which the first visual effect overlays the first user video; in response to a user&#39;s confirmation of the preview, uploading, to at least one remote computer, command data for adding the first visual effect to the first user video at the first time window and at the at least one location such that the at least one remote computer performs video editing of combining a first alpha-format video clip for the first visual effect with the first user video in accordance with the command data to generate, a single resulting video in which the first alpha-format video clip for the first visual effect overlays the first user video at the first time window and at the at least one location; and receiving the single resulting video for playing on the mobile terminal, wherein each still image of the series of alpha-format still images comprises a non-transparent visual effect with a transparent background, wherein the first alpha-format video clip comprises a non-transparent visual effect with a transparent background. 
     In the above-described method, the command data identifies the first user video, identifies the first visual effect, specifies the first time window for adding the first visual effect within the time span of the first user video. Adding further involves selecting at least one location for adding the first visual effect within a display area of the first user video, wherein the command data further specifies the at least one location for adding the first visual effect within the display of the first user video. The series of alpha-format still images comprises a first alpha-format still image and a second alpha-format still image immediately following the first alpha-format still image, wherein in the preview the series of alpha-format still images are displayed in sequence such that at a first point in time of the preview, the first alpha-format still image is displayed alone and that at a second point in time of the preview subsequent to the first point, the second alpha-format still image is displayed alone, wherein there is no overlap of two or more alpha-formal still images at a given point in time of the preview. Still in the above-described method, the series of alpha-format still images comprises a first alpha-format still image and a second alpha-format still image immediately following the first alpha-format still image, wherein in the preview the series of alpha-format still images are displayed in sequence such that at a first point in time of the preview, the first alpha-format still image is displayed alone and that at a second point in time of the preview subsequent to the first point, the first and second alpha-format still images are displayed together. At a third point in time of the preview subsequent to the second point, the second alpha-format still image is displayed alone. At the second point, display strength of the non-transparent visual effect of the first alpha-format still image is lower than display strength of the non-transparent visual effect of the first alpha-format still image, displayed at the first point such that the non-transparent visual effect of the first alpha-format still image fades out over time from the first point to the second point. The mobile application comprises a visual effect library storing the series of alpha-format still images for the first visual effect, wherein the visual effect library does not store or comprise an alpha-format video clip for the first visual effect. 
     Another aspect of the invention provides a mobile terminal comprising a touch screen display, a memory and at least one processor, wherein the mobile terminal comprises video editing mobile application software stored in the memory for executing using the at least one processor, wherein the video editing mobile application software does not have the capability of video editing to overlay a user selected visual effect video clip over a user selected user video for generating a single resulting video while offering video editing of adding the user selected visual effect video clip to the user selected user video by computing power of one or more remote computers, the video editing mobile application comprising alpha-format still images corresponding to each of a plurality of visual effects offered therein, the video editing mobile application software configured: to receive a user command for selecting a first user video for editing; to receive at least one user command for adding a first one of the plurality of visual effects to the user selected first user video, wherein adding the first visual effect to the first user video involves selecting the first visual effect, and selecting a first time window for adding the first visual effect within a time span of the first user video; to provide a preview displaying a series of alpha-format still images over the first user video to emulate the first visual effect over the first user video without generating a single video clip in which the first visual effect overlays the first user video; in response to a user&#39;s confirmation of the preview, to upload, to at least one remote computer, command data for adding the first visual effect to the first user video at the first time window and at the at least one location such that the at least one remote computer performs video editing of combining a first alpha-format video clip for the first visual effect with the first user video in accordance with the command data to generate a single resulting video in which the first alpha-format video clip for the first visual effect overlays the first user video at the first time window and at the at least one location; and to receive the single resulting video for playing on the mobile terminal, wherein each still image of the series of alpha-format still images comprises a non-transparent visual effect with a transparent background, wherein the first alpha-format video clip comprises a non-transparent visual effect with a transparent background. 
     In the above-described mobile terminal, the command data identifies the first user video, identifies the first visual effect, specifies the first time window for adding the first visual effect within the time span of the first user video, and specifies the at least one location for adding the first visual effect within the display of the first user video. Adding further involves selecting at least one location for adding the first visual effect within a display area of the first user video, wherein the command data further specifies the at least one location for adding the first visual effect within the display of the first user video. The series of alpha-format still images comprises a first alpha-format still image and a second alpha-format still image immediately following the first alpha-format still image, wherein in the preview of the series of alpha-format still images are displayed at a regular time interval in sequence such that at a first point in time of the preview, the first alpha-format still image is displayed alone and that at a second point in time of the preview subsequent to the first point, the second alpha-format still image is displayed alone, wherein there is no overlap of two or more alpha-formal still images at a given point in time of the preview. 
     Still in the above-described mobile terminal, the series of alpha-format still images comprises a first alpha-format still image and a second alpha-format still image immediately following the first alpha-format still image, wherein in the preview of the series of alpha-format still images are displayed at a regular time interval in sequence such that at a first point in time of the preview, the first alpha-format still image is displayed alone and that at a second point in time of the preview subsequent to the first point, the first and second alpha-format still images are displayed together. At a third point in time of the preview subsequent to the second point, the second alpha-format still image is displayed alone. At the second point, display strength of the non-transparent visual effect of the first alpha-format still image is lower than display strength of the non-transparent visual effect of the first alpha-format still image displayed at the first point such that the non-transparent visual effect of the first alpha-format still image fades out over time from the first point to the second point. The mobile application comprises a visual effect library storing the series of alpha-format still images for the first visual effect, wherein the visual effect library does not store or comprise an alpha-format video clip for the first visual effect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a video editing system according to embodiments. 
         FIG. 2  illustrates a video editing preview on a mobile terminal and corresponding video editing on a server according to embodiments. 
         FIG. 3  illustrates components of a video editing system according to embodiments. 
         FIG. 4  illustrates a visual effect library on a mobile terminal and a corresponding visual effect library on a server according to embodiments. 
         FIG. 5  illustrates superimposing visual effects over a user video according to embodiments. 
         FIG. 6  illustrates a procedure of video editing according to embodiments. 
         FIG. 7A  illustrates an interface of mobile application when a user video is selected according to embodiments. 
         FIG. 7B  illustrates an interface of mobile application when a user navigates a user video according to embodiments. 
         FIG. 7C  illustrates an interface of mobile application when a user enters a command for adding a visual effect using according to embodiments. 
         FIG. 7D  illustrates an interface of mobile application when a user enters a command for adding a visual effect using according to embodiments. 
         FIG. 7E  illustrates an interface of mobile application when a visual effect is selected to be added to a user video according to embodiments. 
         FIG. 8A  illustrates an example timeline of displaying still images of visual effect according to embodiments. 
         FIG. 8B  illustrates an example timeline of displaying still images of visual effect according to embodiments. 
         FIGS. 9A-9C  illustrate setting locations of visual effect on a mobile application according to embodiments. 
         FIGS. 10A-10C  illustrate a preview of visual effect changing its locations according to embodiments. 
     
    
    
     The drawings are provided to illustrate examples and embodiments described herein and are not intended to limit the scope of the invention. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of the invention will now be described with reference to the accompanying drawings. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. 
     Video Editing on Smartphone 
     With the improvement of computing power of smartphones, editing videos can be performed on a smartphone. However, for better management of smartphone resources, and for more sophisticated video editing, it may be desirable to delegate video editing tasks to a computer having more resources and more video editing functionalities. The present invention provides a video editing system and method that utilize at least one mobile terminal for user interface and at least one remote computer for editing user videos. 
     User Instructions on Mobile Terminal and Video Editing on Server 
     Referring to  FIG. 1 , a mobile terminal  100  is connected to a server  200  wired or wireless via the Internet or information network  300 . The mobile terminal  100  includes a mobile application for video editing. The server  200  includes software for editing user videos. In embodiments, a user enters video editing instructions to the mobile application. The mobile application of the mobile terminal  100  presents a preview for the user&#39;s review and confirmation. In response to the user&#39;s confirmation for editing, the mobile application of the mobile terminal  100  sends a video editing request to the server  200 . In response to the video editing request, the server  200  performs editing of the user video and generates a resulting edited video. 
     As illustrated in  FIG. 2 , in embodiments, the resulting video  210  generated by the server  200  corresponds to the preview  110  presented on the mobile terminal  100  in a manner in which for each visual effect included in the preview  110 , the resulting video  210  includes a corresponding visual effect. The resulting video  210  is a single video clip superimposing the user video and at least one visual effect. On the other hand, the corresponding preview is not a single video clip and rather a visual representation of the user video along with still images that correspond to the at least one visual effect. In embodiments, to present the preview of video editing, the mobile terminal  100  stores still images of visual effects. On the other hand, the server  200  stores video clips that correspond to the still images stored in the mobile terminal&#39;s library. 
     Video Editing System 
       FIG. 3  illustrates components of the mobile terminal  100  and the server  200  of a video editing system according to embodiments. The mobile terminal  100  includes a mobile application  120 , a visual effect library  140  and a user video storage  160 . The server  200  includes video editing software  220  and a visual effect library  240 . 
     Mobile Terminal 
     In this disclosure, the term “mobile terminal” refers to mobile consumer electronic devices, such as smartphones, tablet computers, laptop computers, wearable computing devices, and other mobile computing devices. In embodiments, the mobile terminal includes a display, a user input device, a memory and at least one processor for executing software. In some embodiments, the mobile terminal includes a touch screen display although not limited thereto. 
     Server 
     In this disclosure, the term “server” refers to one or more computers that are typically stationary rather than mobile, although not limited thereto. In some embodiments, the server is at least one networked computer of a service provider for providing video editing services. 
     Mobile Application 
     The mobile application  120  is software installed on mobile terminal  100  and capable of accessing components of mobile terminal  100  for providing user interfaces for video editing. The mobile application  120  communicates with the video editing software  220  of the server  200  for delegating a video editing task to the server  200 . The mobile application  120  provides user interfaces for receiving user commands for video editing, providing a video editing preview, and playing an edited or resulting video from the server  200 . 
     Visual Effect Library of Mobile Application 
     The visual effect library  140  is data store of visual effects for use in the mobile application  120 . In embodiments, the visual effect library  140  stores a plurality of sets of still images, in which each set of still images represents one visual effect. As illustrated in  FIG. 4 , the visual effect library  140  further stores information and data relating to the visual effects (A, BB, . . . AZ). For each visual effect, in embodiments, the visual effect library  140  stores an identification (ID), an accompanying sound recording, the number of still images (image count), etc. In other embodiments, the visual effect library  140  includes addresses or locations of the still images for each visual effect. 
     Visual Effects 
     In the present disclosure, the term “visual effect” or “visual effects” refer to one or more visual objects for adding to a user video. The visual object may be stationary or moving on a screen. The visual object may be colored and translucent, but not a filter to apply to a full screen of frames of the user video. When added to the user video, a visual effect may accompany with a sound recording. 
     Still Images for Visual Effects 
     A set of still images for each visual effect are snapshots or frames of a corresponding visual effect video. In embodiments, each still image includes one or more non-transparent objects or portions on a transparent background, referred to as an alpha (α) format still image. The still images of a visual effect are to be overlaid over user video frames on the mobile application  120  in a preview without forming an integrated video. 
     User Video Storage 
     The user video storage  160  is data store for user videos. In embodiments, the user videos stored in the user video storage  160  include videos captured at the mobile terminal  100  and/or videos downloaded from other sources. 
     Video Editing Software of Server 
     The video editing software  220  is software of the server  200  for performing video editing tasks based on a request from the mobile application  120 . Video editing by the video editing software  220  is, among others, combining a user video and at least one visual effect video such that the resulting video is in a single file and the visual effect video overlaps some frames of the user video. 
     Visual Effect Library of Server 
     The visual effect library  240  is server-side data store of visual effects. In embodiments, the visual effects library  240  of the server  200  stores video clips for visual effects (A, BB, . . . , AZ), e.g., one video clip for a visual effect. As illustrated in  FIG. 4 , the visual effect library  240  further stores information and data relating to the visual effects such as an identification (ID), a frame rate of the video clip (frame per second, fps), an accompanying sound recording, etc. 
     Video Clips for Visual Effects 
     Each video clip for a visual effect includes a transparent background and one or more non-transparent objects or portions, referred to as an alpha (α) format video clip. The frames of the video clip are to be integrated with user video frames to form a single edited video by video editing. In embodiment, alpha (α) format that supports an alpha (α) channel for storing transparency information of each pixel is used for the visual effect video clip. 
     Visual Effects in Visual Effect Libraries of Mobile Terminal and Server 
     Referring to  FIG. 4 , in embodiments, each visual effect has still image data in the mobile terminal  100  and video data in the server  200 . With regard to the visual effect A, for example, a series of still images (A 1 -A 10 ) are stored in the visual effect library  140  of the mobile terminal  100 , and a video clip (A) is stored in the visual effect library  240 . 
     Relationship Between Video Clip and Still Images 
     For each visual effect, the video clip stored in the server  200  directly corresponds to the still images stored in the mobile terminal. In some embodiments, the still images A 1 -A 10  are a subset of frames selected from the corresponding video of visual effect A. In some embodiments, each still image is a snapshot or frame of the video clip or a modified or simplified version of the snapshot or frame. In embodiments, for each visual effect, the number of still images (image frame count) is substantially less than the number of frames in the corresponding video (video frame count). For example, the video frame count is 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 and 200 times greater than the image frame count for the visual effect. In embodiments, the ratio of the video frame count to the image frame count is in a range formed by any two numbers listed in the previous sentence. 
     Example Video Editing 
       FIG. 5  illustrates an example timeline of video editing according to embodiments, in which a user video for editing runs from to through t 6 . In the illustrated example, the visual effect A  520  is superimposed over the user video  510  from t 1  to t 3 , and the visual effect B  530  is superimposed over the user video  510  from t 2  to t 5 . In the example, between t 2  and t 3 , both visual effect A and visual effect B are superimposed with the user video  510 . 
     Example Video Editing Procedure 
       FIG. 6  illustrates an example procedure of video editing. First, a user activates the mobile application  120  on the mobile terminal  100 . Then, at  610 , the user selects a user video  510 . Subsequently, at  620  the user selects a visual effect and at  630  selects parameters for adding the visual effect to the selected user video. In embodiments, the user may add more than one visual effect as in  FIG. 5 . Subsequently, at  640  the mobile application  120  plays a preview for the user&#39;s review and confirmation of adding the visual effects. In response to confirmation, at  650 , the mobile application generates a video editing request for sending to the server  200  at  660 . In response to the video editing request, at  670  the server  200  edits the user video in accordance with the request. Subsequently, at  680  completion of the video editing is notified to the mobile application  120 , and at  690  the user may play the edited video on the mobile application  120   
     Selecting User Video 
     At  610  the user selects a user video from user videos stored in the user video storage  160 . In response, the mobile application  120  displays a scene of the user video  510  and provides a user interface for navigating a timeline of the selected user video  510 . In the alternative to selecting one from the user video storage  160 , the user may select a video for editing from the Internet or a network. Then, the mobile application  120  may download the selected user video or part of the selected video for displaying on its user interface. 
     Selecting Visual Effect and Setting Parameters 
     At  620 , the user selects one or more visual effects to add to the user video. In embodiments, the mobile application  120  provides a user interface for selecting a visual effect from the visual effects available in the visual effect library of the mobile terminal  100 . Subsequent to selection of each visual effect, e.g. visual effect A, at  630 , the user sets one or more parameters for the selected visual effect A via the user interface of the mobile application  120 . In embodiments, the parameters include time frame (start-end), size, orientation, location within the screen, and display strengths (degree of transparency) of the visual effect A. As the user selects visual effects and their parameters, the mobile application  120  saves the user selections and settings. 
     Preview 
     Subsequently, at  640 , a preview of video editing may be displayed at the user&#39;s request. In embodiments, the preview is a play of the selected user video along with the still images of the selected visual effects that are superimposed over the user video frames in accordance with the user&#39;s setting of the parameters. In embodiments, the preview is not an integrated video, in which the still images are incorporated or integrated with the user video. In other embodiments, at least part of the still images may be integrated with or incorporated into the user video to provide the preview. The user may approve the preview or goes back to steps  620  and  630  for changes. 
     Request for Video Editing 
     Subsequently at  650 , the mobile application  120  generates and sends a video editing request to the server  200  at the user&#39;s command. The video editing request includes details of the user&#39;s selections and settings for video editing. In embodiments, the video editing request includes the selected user video, identification of selected visual effect and parameters for each visual effect. In some embodiments, the video editing request includes identification or location information of the user video rather than including the user video data itself. 
     Video Editing at Server 
     At  670 , the video editing software  220  of the server  200  performs video editing in accordance with the video editing request from the mobile application  120 . The video editing software  220  retrieves the selected user video if needed. Also, the video editing software  220  retrieves the video clip for each visual effect identified in the video editing request. Then, the video editing at the server  200  relates to combining the video clip of the selected visual effect with the selected user video as specified by the parameters included in the request from the mobile application  120 . 
     Combining Videos to Add Visual Effects 
     During video editing, the video editing software  220  superimposes frames of the video clip of the selected visual effect over frames of the user video based on the timeframe specified in the video request. Specifically, in the video editing, a frame of the visual effect video clip and a frame of the user video are integrated as a single frame such that the video editing results in a single integrated video incorporating visual effect from the video clip in the user video. To do the frame-by-frame integration, in some embodiments, the video editing software  220  may determine if the frame rates of the user video and visual effect video clip and adjust the frame rate of the visual effect video clip to match the frame rate of the user video. 
     Example Mobile Application Interfaces 
       FIGS. 7A-7E  illustrate example user interfaces of the mobile application  120  for video editing. Referring to  FIG. 7A , a first window  810  of the mobile application  120  displays the starting frame (t 0 ) of the user video  510 . A second window  820  of the mobile application  120  displays a video time-bar  822  showing frames of the user video  510 . In the second window  820 , the mobile application  120  provides an indicator  824  indicating position of the current frame (scene) displayed in the first window  810  on the video time-bar  822 . The mobile application  120  graphical provides icons  830  representing video editing available in the mobile application. Each of the icons  830  represents color adjusting, adding background music, overlaying visual effects, and trimming. In  FIG. 7B , the mobile application  120  displays the first scene (t 1 ) of the user video  510  as the user moves the video time-bar  822 . 
       FIG. 7C-7E  illustrates interface of the mobile application  120  when the user selects the visual effect A and selecting parameters of the visual effect A at the steps of  620  and  630 . In  FIG. 7C , the mobile application  120  displays multiple icons  840  showing visual effect categories available when the user selects an icon  831  of overlaying visual effects among the icons  830 . In  FIG. 7D , the mobile application  120  displays multiple icons  843  representing visual effects in the selected category when the user selects an icon  842  representing heart-shape visual effects. 
     When the user selects the icon  844  (representing the Visual Effect A  520 ) the mobile application  120  displays a con  860  indicating location and size of the visual effect A in the first window  810  over a scene of the user video  510 . The mobile application  120  displays a time line  850  for indicating start/end of the visual effect A. The timeline  850  is sized and aligned with the video time-bar  822  for indicating a corresponding portion of the user video  510  where the visual effect A will be combined. In embodiments, the mobile application  120  provides the icon of the Visual Effect A using at least one form the still images A 1 -A 10 . In embodiments, the user can set a starting point of the visual effect by moving the time line  850  relative to the time bar  822  of the user video. In some embodiments, the user can adjust size of the visual effect A by dragging a size-adjusting mark  862  provided along with the icon  860 . When the user selects the confirm icon  870  the mobile application  120  provides a preview of the visual effect A over the user video  510 . 
     Presentation of Visual Effect in Preview 
       FIG. 8A  illustrates an example timeline of displaying still images of a visual effect A ( FIG. 5 ) in a preview. The visual effect A begins at t 1  and continues until t 3  (t 1 +5 second). In the illustrated example of  FIG. 8A , each still image stays for 0.5 sec. in the preview such that each still image is presented along with multiple frames of the user video  510 . Specifically, in the first time segment from t 1  to t 1 +0.5, the first still image A 01  is displayed over the frames of the user video  510  in the same time segment. For the following segment, from t 1 +0.5 to t 1 +1.0, the second still image till image A 02  is displayed over the frames of the user video  510  in the same time segment. In other embodiments, based on user settings and/or input, the time segment for each still image may change. 
     Showing Still Images in Preview 
     In some embodiments, the mobile application  120  displays the still images A 1 -A 10  one after another in sequence without overlapping with each other as in  FIG. 8A . In other embodiments, as in  FIG. 8B , two or more still images may be displayed at a given time during preview. In some embodiments, the transparency (display strength) of the object(s) included in each still image is constant and does not change over time during the time segment in which the particular still image is presented in the preview. In other embodiments, the transparency (display strength) of the object(s) included in each still image changes over time during the time segment in which the particular still image is presented in the preview. 
     On-Off Display Strength (Transparency) of Objects in Still Image 
     In the example of  FIG. 8A , each of the still images A 01 -A 10  is displayed at either of 100% displays strength and 0% displays strength during display of the visual effect A in preview. For example, still image A 01  is at 100% during the first time segment and at 0% for the rest of time segments. Display strength of 100% is 0% transparency, which is to display the object(s) of each still image as original. Display strength of 0% corresponds 100% transparency, which will result in no display of the object(s) of visual effect. In embodiment, alpha (α) format that supports an alpha (α) channel for storing transparency information of each pixel of the still images are used for changing displays strength. 
     Staggering Display Strength and Overlapping Display of Still Images 
     In the example of  FIG. 8B , the still image A 09  is displayed in the time segment between t 1 +4.0 and t 1 +5.0. The display strength of the still image A 09  gradually increases (fade-in) to its peak at t 1 +4.5 and then gradually decreases (fade-out) until t 1 +5.0. From t 1 +4.0 to t 1 +4.5, the still image A 09  is displayed together with the still image A 08  as the still image A 08  fades out. Similarly, from t 1 +4.5 to t 1 +5.0, the still image A 09  is displayed together with the still image A 10  as the still image A 10  fades in. In the illustrated example, while ending of still image A 08  an beginning of still image A 10  coincide at the time t 1 +4.5, in other embodiments, beginning of still image A 10  may be delayed such that there is some time period in which only the still image A 09  is displayed as visual effect along with the user video frames. Also, in other embodiments, the still image A 10  may begin before complete disappearance of the still image A 08 . The overlapping display and staggering display strength individually and in combination are advantageous as the display of these still images can generate smoother motions with a smaller number or count of still images than the on-off display strength as illustrated in  FIG. 8A . 
     Visual Effect Changing Locations 
       FIGS. 9A to 9C  illustrates setting different locations of the visual effect A at multiple points of the timeline of user video.  FIGS. 10A to 10C  illustrates a preview of the visual effect A changing its locations along the timeline of the user video. Referring to  FIGS. 9A to 9C , visual effect icons  962 ,  964 ,  966  represent a visual representation of the visual effect A at corresponding points  952 ,  954 ,  956  in the timeline  850 . The user can adjust location of the visual effect A at the point  952  by moving the moving visual effect icons  962  as in  FIG. 9A . Similarly, the user can change locations of the visual effect A at the points  954 ,  956  in the timeline  850  by moving the icons  964 ,  966 . For each of the points  952 ,  954 ,  956  the mobile application  120  stores the location of the visual effect as part of meters for video editing. The mobile application  120  includes the stored locations in a request for server-side video editing. Based on the request, the server  200  generates a resulting video in which the visual effect A moves along a trace connecting the multiple locations of  962 ,  964 ,  966 . In some embodiment, parameters of the visual effect A for overlaying include different settings of the visual effect A at two or more points in the timeline of the visual effect A. 
     Mobile Application—Not performing Video Editing by Itself 
     In embodiments, mobile application  120  does not perform, by itself, a video editing to combine visual effects to user videos because such video editing task is too heavy for limited computational power of the mobile terminal  100 . Instead, the mobile application  120  provide of a video editing and delegates the video editing to the server  200  to take advantage of computational power of the server  200 . In embodiments, a preview of visual effects is provided using-still-images representing the visual effects without using a video clip of the visual effects. Process of providing a video editing preview is not a simplified version of corresponding video editing at the server because the mobile application  120  does not modify the user video or create a new video file incorporating the visual effects to the user video. 
     Modifications, Combinations and Sub-Combinations 
     Although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that various features and aspects of the present invention extend beyond the specifically disclosed embodiments to other alternative embodiments. In addition, while a number of variations have been shown and described in detail, other modifications, which are within the scope of the invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, and that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as set forth in the following claims.