VVC support in Matroska

[MasterQuestionable]

͏    2025-01-08-git-251de1791e-full_build-www.gyan.dev

͏    ffmpeg -v debug -hide_banner -nostdin -nostats -f lavfi -i "testsrc2=1920x1080:30:d=5" -c:v libvvenc "Out.mkv"
͏    ffplay -v trace "Out.mkv"
[vvc] nal_unit_type: 14(VPS_NUT), nuh_layer_id: 36, temporal_id: 5
[vvc] nal_unit_type: 15(SPS_NUT), nuh_layer_id: 0, temporal_id: 0
[vvc] nal_unit_type: 16(PPS_NUT), nuh_layer_id: 0, temporal_id: 0
[vvc] Invalid value at vps_layer_id[i]: bitstream ended.
[vvc] Failed to read unit 0 (type 14).
[matroska,webm] Failed to open codec in avformat_find_stream_info
[NULL] Failed to parse extradata.
[NULL] nal_unit_type: 20(AUD_NUT), nuh_layer_id: 0, temporal_id: 0
[NULL] nal_unit_type: 15(SPS_NUT), nuh_layer_id: 0, temporal_id: 0
[NULL] nal_unit_type: 16(PPS_NUT), nuh_layer_id: 0, temporal_id: 0
[NULL] nal_unit_type: 17(APS_PREFIX), nuh_layer_id: 0, temporal_id: 0
[NULL] nal_unit_type: 7(IDR_W_RADL), nuh_layer_id: 0, temporal_id: 0

͏    Out of curiosity I decided to test...
͏    Very-slow-broken Video Codec?

[Frank Plowman]

Matroska does not support VVC. I feel like there should be an error message or warning if you try to encode a Matroska VVC file, but this is out of my ballpark.

Without the container involved, the sample plays fine:
ffmpeg -f lavfi -i "testsrc2=1920x1080:30:d=5" -map 0 -c:v libvvenc -f data "out.vvc"

ffplay out.vvc

[Frank Plowman]

Replying to Frank Plowman:

Matroska does not support VVC. I feel like there should be an error message or warning if you try to encode a Matroska VVC file, but this is out of my ballpark.

It looks like maybe some newer versions of Matroska do support VVC (drafts?), but regardless this is a container and not a codec issue.

[James]

It is supported. See ​https://github.com/ietf-wg-cellar/matroska-specification/blob/master/codec_specs.md#v_mpegiisovvc

I'll send a patch to add support for it.