[Gigachad]

I went and checked some youtube videos on my front page, A video with 15k views had an AV1 encode, while a video with 160 views was h264 only. So extremely popular videos is not how I would describe it, probably by views, almost everything you watch on youtube is AV1. But they skip the extra encodes for videos relatively no one watches.

[ksec]

Last time I checked they do it for new videos only. Older videos with 1M views aren't even on AV1.

[Gigachad]

Makes sense, new videos are where most of the streams are happening, I wouldn't be surprised if they start to reduce the number of transcodes to save space as a video drops in popularity. h264 will work on everything so they need that as a minimum, with AV1 just being there to save on data transfer.