Conversion Script from MP4 to WebM in good quality

mp4_to_webm.sh

#!/bin/sh
set -ex

for i in *.mp4; do
	ffmpeg -y -i "$i" -c:v libvpx-vp9 -pass 1 -b:v 2M -crf 30 -threads 8 -speed 4 \
	  -pix_fmt yuv420p -tile-columns 6 -frame-parallel 1 \
	  -an -f webm /dev/null


	ffmpeg -i "$i" -c:v libvpx-vp9 -pass 2 -b:v 2M -crf 30 -threads 8 -speed 2 \
	  -pix_fmt yuv420p -tile-columns 6 -frame-parallel 1 -auto-alt-ref 1 -lag-in-frames 25 \
	  -c:a libopus -ac 2 -b:a 128k -f webm $(basename "${i/.mp4}").webm

done