Accessibility/Video Codecs: Difference between revisions

A video consists of multiple tracks of data temporally multiplexed (or: interleaved) with each other such that at any point in time the data from all tracks relevant to that time is not "far away". To be a video, there has to be at least a video track and a audio track. There can be, however, multiple audio tracks (e.g. multiple languages), multiple video tracks (e.g. different camera angles), multiple timed text tracks (e.g. subtitles in different languages), and other tracks, such as timed images (e.g. slides of a presentation) or lighting information for a concert etc.

To multiplex these multiple tracks of data together into one file (or stream), there is a container (or encapsulation format).

Thus, the simplest video with a caption consists of a container, a video codec, an audio codec and captions that have been multiplexed as a timed text codec.