[FFmpeg-devel] [PATCH] avcodec/h264_parser: remove key frame tagging heuristics

[Derek Buitenhuis]

On 7/13/2021 1:22 AM, James Almer wrote:
> Because it isn't something that should be marked as a keyframe as coded 
> bitstream in any kind of container, like it's the case of mp4 sync samples.

It *is* something that should be specifically marked in MP4, though, which
does vhae proper facilities for this stuff. The problem is our API has no concept
of RAPs other than "is an IDR".

Proper way to write e.g. intra-refresh streams is:
 * Write the 'sdtp' box.
 * Write the 'sgpd' and 'sbgp' boxes with a 'roll' sample grouping type and roll_distance properly set. 

Annex I of the MP4 spec is quite clear how all types of recover and sync points should be written.

- Derek