4chan ffmpeg-webm conversions guide

>general conversion
ffmpeg -i [input video] -ss [start time] -t [length] -codec:v vp8 -an [output video].webm

>gif conversion
ffmpeg -i your_weeaboo_gif.gif -codec:v vp8 -an [output video].webm

>youtube to webm (requires youtube-dl)
youtube-dl https://www.youtube.com/watch/?v/=[whatever] -o - | ffmpeg -i - -ss [start time] -t [length] -codec:v vp8 -an [output video].webm