AVMutableComposition is a mutable subclass of AVComposition you use when you want to create a new composition from existing assets. You can add and remove tracks, and you can add, remove, and scale time ranges.
AVMutableComposition is a mutable subclass of AVComposition you use when you want to create a new composition from existing assets. You can add and remove tracks, and you can add, remove, and scale time ranges.
At its top-level, AVComposition is a collection of tracks, each presenting media of a specific media type, e.g. audio or video, according to a timeline. Each track is represented by an instance of AVCompositionTrack. Each track is comprised of an array of track segments, represented by instances of AVCompositionTrackSegment. Each segment presents a portion of the media data stored in a source container, specified by URL, a track identifier, and a time mapping. The URL specifies the source container, and the track identifier indicates the track of the source container to be presented.
Sources:
- AVMutableComposition Class Reference (paragraph 1)
- AVComposition Class Reference (paragraph 2)
