VP8

Here's how to encode to a VP8/Vorbis WebM file:

ffmpeg -i SOME_VIDEO.mkv -threads 8 -f webm -vcodec libvpx \
   -g 120 -level 216 -profile 0 -qmax 42 -qmin 10 -vb 2M \
   -acodec libvorbis -aq 50 -ac 6 SOME_VIDEO.webm

Requires ffmpeg >= 0.60

References

• http://wiki.hydrogenaudio.org/index.php?title=Recommended_Ogg_Vorbis
• http://www.ffmpeg.org/ffmpeg-doc.html