Turn a movie into an animated webp.

awebp.sh

#!/bin/zsh
movieInput=$1
tmpFolder=$2
outName=$3

mkdir -p $tmpFolder
ffmpeg -i $movieInput $tmpFolder/%03d.png

for i in `ls $tmpFolder`; do
  j=`echo $i | sed s/\.png/.webp/`
  cwebp $tmpFolder/$i -o $tmpFolder/$j
done

webpmux `for i in \`ls $tmpFolder/*.webp\`; do echo -n "-frame $i +33+0+0+1+b "; done` `echo -n $4` -o $outName

# To cheat a none looping animation, add the last frame again with a really
# long timeout. A slightly higher value can be given then below but the below
# value is already more than 2 days.
# -frame last-frame.webp +9999999+0+0+1+b