Put av1 in matroska instead of WebM

[Cuteistfox]

describe the feature you'd like to see

According to wikipedia AV1 in WebM is unoffical. Instead you should use mastroska. WebM is just a limited subset of matroska.

additional context

No response

[wukko]

webm is way more compatible tho, mkv support kind of sucks

[firsturdiev]

Why you didn't use mp4 as container?