VLC: how to generate .m3u playlists

1 Syntax of .m3u

An .m3u file is a plain text file that specifies the locations of one or more media files. Each entry carries one specification, which can be:

1. an absolute local path:C:\Music\I_love_this_one.mp3
2. a relative path: This_one_as_well.mp4
3. an URL: www.music.com/123.mkv

The extended .m3u syntax we will use in the script: 1. #EXTM3U: file header, should be the first line 2. #EXTINF: track information: #EXTINF:123,Title

All the syntax for .m3u can be checked on Wikipedia.

2 My file system

tree Music -L 1

Music/
├── Dr._Dre
│   ├── 02 - Deep Cover.flac
│   ├── ...
├── Imagine_Dragons
├── LOL_BGM
├── OneRepublic
├── The_Fat_Rat
└── The_Music_of_Grand_Theft_Auto_V

And all those files are published on the Internet, so they can be accessed by http://ipv4.bajzc.com:81/Music/... (use port 81 as the NSP blocked the default port: 80)

3 Script

#! /bin/bash
set -e
export ListPath=/var/www/html/PlayLists
Backup(){
  cd $ListPath
  for name in $(ls -c)
  do
        mv $name ./.$name.bak
  done
}

ListMovie(){
cd $ListPath/../
echo "#EXTM3U" >> $ListPath/ALL.m3u
find Movie/ -mindepth 1 -maxdepth 2 | while read line
do
        if [ -d "$line" ]; then
        echo -n "#EXTGRP " >> $ListPath/ALL.m3u
        echo $(echo "$line" | sed -e "s/\([[:print:]]*\/\)*//g") >> $ListPath/ALL.m3u
  else
        duration=$(ffmpeg -i "$line" 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }')
        if [ "$duration" == "0" ] || [ "$duration" == "" ]; then
          printf "$line is not a media file, duration: $duration\n"
          continue
        fi
                echo -n "#EXTINF:$duration," >> $ListPath/ALL.m3u
        echo $(echo "$line" | sed -e "s/\([[:print:]]*\/\)*//g") >> $ListPath/ALL.m3u
        echo $(echo "$line" | sed -e 's/^/http:\/\/ipv4.bajzc.com:81\//') >> $ListPath/ALL.m3u
        echo >> $ListPath/ALL.m3u
        fi
done
}

ListAlbum(){
  cd /var/www/html/
  find Music/ -maxdepth 1 -mindepth 1 -type d | while read line
  do
        Album=$(echo "$line" | sed -e "s/\([[:print:]]*\/\)*//g")
        echo $Album
        echo "#EXTM3U" > $ListPath/$Album.m3u
        echo "#EXTGRP" >> $ListPath/$Album.m3u
        echo "#EXTGRP" >> $ListPath/ALL.m3u
        find $line -type f | while read path
        do
          duration=$(ffmpeg -i "$path" 2>&1 | grep "Duration"| cut -d ' ' -f 4 | sed s/,// | sed 's@\..*@@g' | awk '{ split($1, A, ":"); split(A[3], B, "."); print 3600*A[1] + 60*A[2] + B[1] }')
          if [ "$duration" == "0" ] || [ "$duration" == "" ]; then
            printf "$path is not a media file, duration: $duration\n"
            continue
          fi
        header="#EXTINF:$duration,$(echo "$path" | sed -e "s/\([[:print:]]*\/\)*//g")"
        url="$(echo "$path" | sed -e 's/^/http:\/\/ipv4.bajzc.com:81\//')"
        printf "$header\n$url\n\n" >> $ListPath/$Album.m3u
        printf "$header\n$url\n\n" >> $ListPath/ALL.m3u
        done
  done
}

compress(){
  cd $ListPath
  tar -czvf PlayList.tar.gz *.m3u
  zip -qr PlayList.zip *.m3u

}
Backup
ListMovie
ListAlbum
compress
unset ListPath

Backup()

line 6-9: backup all files in $ListPath

ListMovie()

line 13: change the directory to where the Movie is.

line 14: print .m3u header to the output file $ListPath/ALL.m3u

line 15: list all the files and directories in Movie/ and assign the path to line

line 17: whether line is a path to a directory

line 19: use regular expression to get the name of directory

line 21: use ffmpeg to get the duration of a media file in seconds

line 28: use regex again to convert the relative path into URL

ListAlbum()

line 36: only search for directories in one depth

line 38: use regex to get the name of album

compress()

line 60: compress into .zip

line 61: compress into .tar.gz

The output can be seen here

4 Summary

This script still has some limitations, such as it cannot deal with the SPACE in directories' name. Because find won't return the path in C-style (while ls can do it). For example: The Music of Grand Theft Auto V, should be The\ Music\ of\ Grand\ Theft\ Auto\ V. Otherwise Bash cannot locate it.

However, if the file name contains those characters will be fine. Thanks to ffmpeg, path can be passed as a string. (Line 21)

After all, open a m3u file in VLC: