AVC1 is just H264[0]. FFmpeg says stream 0 is "Video: h264" The page you linked about AV1 in mp4 says it uses MPEG-4 Part 31, which is under development and no

AVC1 is just H264[0]. FFmpeg says stream 0 is "Video: h264" The page you linked about AV1 in mp4 says it uses MPEG-4 Part 31, which is under development and not final [1]. Until now I was not aware they were extending the MPEG-4 container standard to include more formats. [0] https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Naming https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Naming [1] https://www.iso.org/standard/66062.html https://www.iso.org/standard/66062.html