Synchronizing audio and video components of an automatically generated audio/video presentation

Abstract

Some embodiments provide an application that can automatically generate a movie from a collection of media clips stored on a device or accessible by the device. The movie creation process of some embodiments uses novel video and audio compositors that dynamically composite video and audio components of the movie. The video compositors process explores different combination of media clips and media-clip arrangements to produce an interesting video presentation. The audio compositor receives the duration of the video presentation, and dynamically generates a song for the video presentation based on this duration. Another novel interaction is that in some embodiments the audio compositor provides the starting location of its last segment to the video compositor so that the video compositor can align the start of the last video segment with this ending segment. In some embodiments, the video and audio compositors also synchronize fade-out effects that they apply to their respective presentations with each other. Also, in some embodiments, the video compositor can ask the audio compositor for one or more audio onsets that are near a particular time in the presentation. In some of these embodiments, the audio compositor returns (1) a list of onsets that are near a time that is specified by the video compositor, and (2) a priority for each of these onsets. The video compositor then uses this list of onsets to align an edit point in the composite video's definition to the location of one of the onsets based the specified priority value(s) and the desirability of the video edit at the onset location.