>>4885
Didn't work, it still says the file is corrupt in librewolf and still says yuv420p10 in mpv. Maybe the codec you're using is forcing it to be 10bit? Here's what I use:

ffmpeg -i "i.mp4" -c:v libvpx-vp9 -crf 35 -b:v 0 -row-mt 1 -tile-columns 1 -tile-rows 0 -frame-parallel 0 -auto-alt-ref 1 -lag-in-frames 25 -pix_fmt yuv420p -c:a libopus -b:a 32k "o.webm"

lower crf = higher quality