Possibility: Add function for getting the Sequence Header OBU

[dwbuiten]

Not sure if this belongs here on the rav1e repo (will move depending on where it should be).

[20:40] < jamrial> so rav1e_container_sequence_header() returns the first four bytes defined in that configuration box, but not the actual seq header obu? O_o
[20:40] < Daemon404> yeah
[20:40] < Daemon404> spec says 'zero or more'
[20:40] < Daemon404> i can fix it probably but that's what it does right now
[20:41] < jamrial> it would ideally include it, yeah. but also, it would be nice to have a function that simply returns the seq header alone
[20:45] < Daemon404> for what use case?
[20:48] < jamrial> right now, extradata within avcodec/avformat is raw obus only. those four bytes are generated by a muxer if required (mov, mkv/webm)
[20:48] < jamrial> but i guess it would be a matter of propagating the seq header without the first four bytes, so no need for a second function
[20:49] < Daemon404> hmm OK
[20:50] < Daemon404> i'll open an issue and see what people think
[20:50] < jamrial> just making that function return a seq header as part of the config OBUs would be enough to remove the extract_extradata bsf from the wrapper
[20:51] < Daemon404> OK