This replaces mux.js for CEA608 decoding. Applications will no longer need to include mux.js for CEA support, and mux.js will only be necessary for TS transmuxing.
Closes#2648
This is an MP4 Parser which extracts CEA-708 packets from Fragmented MP4 streams.
The Closed Caption Parser (shaka.media.ClosedCaptionParser) will own this MP4 Parser, and will initialize it and call it as shown. As data comes in, the parser will parse this data, and the caption packets data then be returned in a callback (on708Data), as shown. Here, a theoretical decoder (future pull request, mentioned as a Todo comment) will decode and extract the parsed captions from these packets.
Issue #2648