>>35291488(me)the av1 appears to be a recode but i can't really tell if avc or vp are better both have some banding artifacts going on but slightly different.
Order is av1 vp9 h264
filterchain for those interested
ffmpeg -i .\av1_399.mp4 -i .\vp9_248.webm -i .\h264_137.mp4 -an -lavfi "nullsrc=size=5760x1080 [a];[a][0:v] overlay=shortest=1 [b:lit];[b:lit][1:v] overlay=shortest=1:x=1920 [c];[c][1:v] overlay=shortest=1:x=3840 [d];[d] select=gte(n\,11*25)" -vframes 1 compare_frame.png