Closed captioning media
Store closed captioning for QuickTime movies.
Overview
A closed caption media track contains text data used for closed captioning in QuickTime movies. It has a media type of 'clcp'. Closed captions are used to display the audio portions of a movie as text. They transcribe dialog and indicate other sounds.
Other tracks can identify this track as being a related closed captioning track by using the 'clcp' track reference to refer to this track.
Like other media data tracks, a closed caption track should include a language code and an extended language tag atom.