4chan basic webm encoding guide with FFmpeg

Make your own webms for 4chan and fight the merchant menace on /gif/ today!

Notes:
for /wsg/ just increase the filesize limit to 6 MB.
the unknown song is SALES - renee

ffmpeg code snippets

mp4 to webm
ffmpeg -i yourvid.mp4 -threads 4 -c:v libvpx -c:a libvorbis -b:v 400k -b:a 192k -quality good -qmin 0 -qmax 50 -metadata title="check my first webm!" test.webm

gif with sound to webm
ffmpeg -stream_loop -1 -r 38 -i kanna.gif -i neatloop.mp3 -threads 4 -c:v libvpx -c:a libvorbis -b:v 400k -qmin 0 -qmax 50 -t 26.3 -auto-alt-ref 0 -quality good -metadata title="test" kannaloop.webm

image with sound to webm
ffmpeg -loop 1 -r 1 -i alencia.png -i childrenofvhs.mp3 -c:v libvpx -c:a libvorbis -b:v 10k -b:a 64k -vf scale=640:-4 -pix_fmt yuv420p -threads 4 -quality good -metadata title="test" -shortest -fs 3999k alencia.webm

Full documentation: https://www.ffmpeg.org/ffmpeg.html
Wiki: https://trac.ffmpeg.org/
Cheat Sheat: https://gist.github.com/steven2358/ba153c642fe2bb1e47485962df07c730