This paper is based on Jan Ozer‘s analysis.
1) For less 1080p resolutions, YouTube selects the codec according to view count:
- AV1 for videos with view counts above half-million
- VP9 for videos with view counts from several thousands to half-million
- H264 for low view counts (less several thousands)
Notice that hevc is not used by YouTube at all.
For details pls. see
2) For 1080p to 4K resolutions YouTube uses both AV1 and VP9, for details
23+ years’ programming and theoretical experience in the computer science fields such as video compression, media streaming and artificial intelligence (co-author of several papers and patents).
the author is looking for new job, my resume
