If you have a file that requires this codec string (e.g., for remuxing, streaming, or media info validation), correct it as follows:
For MKVToolNix / FFmpeg:
ffmpeg -i input.mkv -c copy -metadata:s:v:0 codec_tag=av01.0.08M.08 output_fixed.mkv
For DASH manifest or MPD:
<Codec>av01.0.08M.08</Codec>
<!-- Bitrate 399000 bps, audio opus itag 251 -->
For HTML5 / JavaScript MSE:
mimeCodec = 'video/webm; codecs="av01.0.08M.08, opus"';
The term AV01008M08 is emerging in technical forums as a placeholder or internal specification for a hybrid A/V sync profile. While not an official codec name (like H.264 or AAC), it appears to describe a constraint set: codecs av01008m08 399 opus 251 new
In practice, AV01008M08 targets 1080p resolution at 8 Mbps—aggressive by 2025 standards, aiming to match H.265 quality at nearly half the bitrate.
The appearance of garbled strings like av01008m08 399 opus 251 new indicates two major trends: If you have a file that requires this codec string (e
From 2025 onward, expect to see av01.0.12M.10 opus 251 (10-bit, level 12) as the new high-end standard. The string 399 will disappear, replaced by av1 + average bitrate in separate JSON metadata.
parts = codec_str.split()
video_codec = parts[1] track_id = parts[2] audio_codec = parts[3] audio_id = parts[4] flags = parts[5:] # ["new"]
print(f"Video: video_codec, Audio: audio_codec") For DASH manifest or MPD: <Codec>av01