Comment by lawrencejgd

It doesn't matter that AVIF uses the same container for AV1 or AV2 based encoding, if the browsers don't have the right decoder for it then they can't decode it.

An example of this is MP4: Browsers can decode videos encoded with H264 in MP4 containers, but not H265 even if it uses the same container, because one thing is the container and another thing is the codec, they're related but they aren't the same.