ffmpeg-based animation converter, converts from * to high quality x264 and good libvorbis, is quite slow, however

ffmpeg-convert-animation.sh

#!/bin/bash

[[ -z $2 ]] && {
  echo "usage $0 /path/to/movie/in /path/to/movie/out" > /dev/stderr
  exit 1
}

PRESET=veryslow
TUNE=animation
CRF=18

ionice -c 3 -p $$
renice +12  -p $$ > /dev/null 2>&1

ffmpeg -i "$1" \
  -c:v libx264 -preset $PRESET -tune $TUNE -crf $CRF \
  -c:a libvorbis -aq 4 \
  "$2"