SOLVED: Jellyfin transcodes as AV1 even though it's not allowed

[pitfallfritz]

Thank you for your replies!

So, the migration to macOS only coincided with me discovering this behavior as I was testing different types of video. To remove this from the equation, I tested this with the original copy of my server running on Debian/amd64.

I selected a video in AVI/XviD/MP3 and played it in Chromium.
Transcode log — https://pastebin.com/WyM193wd
Jellyfin log  — https://pastebin.com/cQbJcRZr
Playback Info — https://imgur.com/a/kD2nL4H or attached

VP1 transcoding speed is abysmal at 7% of realtime, although this is a low-end passive-cooled Intel Atom. The M1 reached about 80% of realtime. For comparison, the same M1 Mac encodes the same video at about 3x realtime in Handbrake using VP9 (medium, CQ25, default settings). Most of all, it should not be allowed to be transcoded to VP9.

Re. Firefox and HEVC:
Yeah, you're right and I had thought so too. Jellyfin transcoded to x264 and I didn't even notice — before the migration HEVC videos in Jellyfin just refused to play in Firefox at all. My bad.