Download a song, convert it to mp3 and resize the thumbnail to be square by fillinf the image with blur

download_mp3.sh

#!/bin/bash
# This requires:
#   - yt-dpl 
#   - ffmpeg
# For convenience, it can be added to alias file (e.g. ~.bash_aliases)


download_mp3() {
  if [ $# -eq 0 ]; then
    echo "Please specify an URL and optionally a destination folder";
    echo "Example:"
    echo "    download_mp3 https://www.youtube.com/watch?v=LDU_Txk06tM 'Crab Rave'"
    return 1;
  fi
  export URL="${1}"
  export DIR="${2}"
  export COVER_SIZE=1024
  if [[ $DIR != "" ]]; then
    if [[ -f "$DIR" ]]; then
      echo "There is already a file with the name '$DIR'. Aborting..."
      return 1
    fi
    if [[ ! -d "$DIR" ]]; then
      (mkdir "$DIR" && echo "Created '$DIR'") || echo "Failed to create directory '$DIR'"
    fi
    cd "$DIR"
  fi;
  yt-dlp \
    --write-thumbnail \
    --convert-thumbnails jpg \
    --embed-thumbnail \
    --ppa "EmbedThumbnail+ffmpeg_o:-c:v mjpeg -vf '[0:v]split=2[blur][vid];[blur]scale=1024:1024:force_original_aspect_ratio=increase,crop=$COVER_SIZE:$COVER_SIZE,boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=1[bg];[vid]scale=$COVER_SIZE:$COVER_SIZE:force_original_aspect_ratio=decrease[ov];[bg][ov]overlay=(W-w)/2:(H-h)/2'" \
    --extract-audio \
    --audio-format mp3 \
    --audio-quality 320K \
    --embed-metadata \
    --keep-video \
    "$URL"
  if [[ $DIR != "" ]]; then
    cd .. # switch back to the original directory
  fi;
}