[peutetre]

You inevitably have to do multiple encodes. An H.264 encode as the "plays anywhere" option and an AV1 encode as the "less bandwidth or better image quality at the same bandwidth" option.

YouTube does H.264, VP9, and AV1 video encodes with AAC and Opus audio encodes.

This video for example has encodes of all those options: https://www.youtube.com/watch?v=ArmDp-zijuc

You can watch it in multiple resolutions and formats from 4K in AV1 down to 144p in H.264.

[KyleSanderson]

This only happens because they're using Cisco's license. H.264 is not "plays anywhere".

[ksec]

By your definition then nothing would be "plays anywhere". H.264 is about the closest you can get. And depending on Profiles it is about to become patent free where license will no longer be required.