ISO 26429-7:2008 specifies the Composition Playlist structure. The Composition Playlist is a self-contained representation of a single complete digital cinema work, e.g. a motion picture, a trailer or an advertisement.
The Composition Playlist consists of an ordered sequence of Reel structures, each referencing a set of external Track Files, e.g. a sound or picture Track File, which are meant to be reproduced in parallel. Each Reel is analogous to a film reel and the Composition Playlist controls the order and timing of the playout of the Reels.