YouTube - which is higher quality - VP9 or AV1?

[flashandpan007]

What is better quality on YouTube in 4K UHD 2160p
VP9 (higher bitrate) vs. AV1 (higher compression)

I know that not all 4K videos are available in AV1 but is there any difference in quality? Why wooden eyes can not decide, so I need to ask others

[Quint]

Load down both.
Cut one frame (the same) out of both, that contains very small details with much colour.
See for yourself.

[jagabo]

Without access to the source video there's no objective way of determining which encoding is more faithful to the original. All you can do is look at the two and say which looks better to you. That's very subjective. In my experience the difference between youtube's AV1 and VP9 encodings is very small. AV1 is a little a little smoother but loses more detail. VP9 retains a little more detail but looks rougher.

Other issues may be more important. Can all your players handle both codecs smoothly? Not many players outside a computer can decode AV1 at this point. More can deal with VP9. Is CPU usage excessive with one of the codecs? Do you need the smaller files to fit more videos on a portable device?

[rrats]

Very subjective. Both should theoretically yield out the same quality which is bad since youtube overcompresses everything