Topic: FFMPEG Presets

Whenever i have to convert mp4 to webm, i just use this (seems to work good enough for me without any visible loss of quality)

ffmpeg -i input.mp4 -b:v 0 -crf 30 -pass 1 -an -f webm -y NUL
ffmpeg -i input.mp4 -b:v 0 -crf 30 -pass 2 output.webm