On a related note is anyone having trouble maintaining transparency from GIFs when converting them to webms? I'm using the following but the piece of shit uses yuv420p instead of the correct yuva420p and it's driving me nuts.
ffmpeg -i test.gif -c:v libvpx -auto-alt-ref 0 -crf 10 -pix_fmt yuva420p -y test.webm
Even more confusing, this DOES work:
ffmpeg -i test.gif out.webp