I made this webm using ffmpeg. Firstly, I ripped a section of video. ffmpeg -i starwars.mkv -vcodec copy -acodec copy -ss 00:19:23 -to 00:19:33 out.mkvffmpeg -i starwars.mkv -vcodec copy -acodec copy -ss 00:19:23 -to 00:19:33 out.mkv Then I did the first pass of two pass encoding. ffmpeg -i out.mkv -c:v libvpx-vp9 -pass 1 -qmin 0 …