Youtube playlist video to mp3 downloader bash script sudo apt-get install youtube-dl ffmpeg or libavcodec-extra-53

get_youtube_playlist

#!/bin/bash
 
usage='usage:
 ./get_youtube_playlist <playlist_id> <target_folder> <num_songs>
   target_folder: (default: songs will be downloaded in current folder)
   num_songs:     number of songs to get (default: 50)
 
examples:
 ./get_youtube_playlist RD02HIkZaLeuF9k
 ./get_youtube_playlist RD02HIkZaLeuF9k "my jazz" 10
'
 
playlist_id=$1
target_folder=$2
num_songs=$3
 
if [ -z "$playlist_id" ]; then
    echo "$usage"
    exit 1
fi
 
if ! [[ "$num_songs" =~ ^[0-9]+$ ]] ; then
    num_songs=50
fi
 
if [ -z "$target_folder" ]; then
    target_folder='./'
elif [ ! -d "$target_folder" ]; then
    echo "Parameter target_folder is incorrect, $usage"
    exit 1
fi
 
 
# use youtube API for getting music list of playlist
# https://developers.google.com/youtube/2.0/developers_guide_protocol_playlist_search
youtube_api="`wget -qO- https://gdata.youtube.com/feeds/api/playlists/$playlist_id\?max-results\=$num_songs`"
if [ -z "$youtube_api" ]; then
    echo "Playlist ID is incorrect, $usage"
    exit 1
fi
 
# list of IDs into songs array
songs=(
    $(echo $youtube_api | \
    grep -P -o "<media:player url='.*?&" | \
    grep -P -o "(\w|-){11}")
)
 
if [ -z "$songs" ]; then
    echo "Nothing to do, $usage"
    exit 1
fi
 
# work with each music video
for (( i = 1 ; i <= ${#songs[@]} ; i++ ))
do
    youtube_id=${songs[$i-1]}
    track_number=`printf "%0*d" 2 $i`
    flv_path="$target_folder/$youtube_id.flv"
    mp3_path="$target_folder/$track_number. $youtube_id.mp3"
 
    # 1. download flv by youtube-dl
    youtube-dl --audio-format=mp3 -o "$flv_path" "http://youtu.be/$youtube_id"
   
    if [ -f "$flv_path" ]
    then
        # 2. flv -> mp3
        #avconv -i "$flv_path" -y "$mp3_path" -acodec libmp3lame -ac 2 -ab 128k -vn
        ffmpeg -i "$flv_path" -acodec libmp3lame -ac 2 -ab 128k -vn -y "$mp3_path"
        # 3. delete flv
        rm "$flv_path"
    fi
done