Summary

This Recommendation specifies the format of back‑channel messages for conveyance of status information and requests from a video receiver to a video sender.

The message syntax has been designed in a generic way to make it applicable for use with the majority of the existing international video coding standards. The application of the generic messages to ITU-T Recs H.261, H.263, and H.264 | ISO/IEC 14496‑10 is specified.