# mux audio into containers. file names in sound and current dirrectories must match. tmp usage for anime downloads.
# usage: ffmpeg_mux_audio <SOUND> <OUTPUT DIR>
ffmpeg_mux_audio()
{
  if [[ "$1" = "" ]]; then
    echo "usage: ffmpeg_mux_audio <SOUND> <OUTPUT DIR>"
    return
  fi

  for file in *; do ffmpeg -i "$file" -i "$1"/"$file" -c copy -map 0:v:0 -map 1:a:0 -shortest "$2"/"$file"; done
}