Author

Alejandro Alcalde

Graduado en Ingeniería Informática en la ETSIIT, Granada. Creador de El Baúl del Programador

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Many of us like to listen to music while programming. Today I thought that it would be nice if I could create a playlist with a fixed length I can choose.

After a little thinking I decided to write a little python script that do the work for me. It accepts as params a directory where the music is, and the duration for the playlist.



Requirements

In order to read the length of each file I’ve used Mutagen. It is easy to install:

$ pip install mutagen

Once installed, we can execute the script, here is the code:

#!/usr/bin/env python

'''
Created on Apr 4, 2014

@author: Alejandro Alcalde

Licensed under GPLv3

More info: http://wp.me/p2kdv9-Bq
'''

import argparse
import fnmatch

from mutagen.mp3 import MP3
from mutagen.mp4 import MP4
from mutagen.flac import FLAC

from os.path import os, basename
from sys import argv
from random import shuffle

curr_length = 0
playlist_number = 1

def main():

    parser = argparse.ArgumentParser(description='Generate playlists with the indicated length')
    parser.add_argument('-d','--directory', help='Directory with music files',type=str, required=True)
    parser.add_argument('-l', '--length', help='Length of the playlist, in minutes', type=int, required=True)

    args = parser.parse_args()

    directory = args.directory
    length =  args.length * 60

    path = r'./playlists/'
    if not os.path.exists(path): os.makedirs(path)

    playlist_basename = 'playlist_' #basename(argv[0][:-3]) + '_'
    curr_items = []
    too_long_items = []
    all_items = []

    for music_file in os.listdir(directory):
        if fnmatch.fnmatch(music_file, '*.mp[43]') or fnmatch.fnmatch(music_file, '*.flac'):
            all_items.append(directory + music_file)

    shuffle(all_items)

    for item in all_items:
        global curr_length
        if curr_length >= length:
            create_playlist(path, playlist_basename, curr_items)
        else:
            encoding = item[-4:]
            encodings = {'.mp3': MP3, '.mp4': MP4, 'flac': FLAC}
            try:
                music_file = encodings[encoding](item)
            except Exception as e:
                handleException(e)
            else:
                file_length = music_file.info.length
                if file_length > length:
                    too_long_items.append(item)
                    print 'File %s exceed the given length (%s min)' % (item, file_length/60)
                else:
                    curr_length += file_length
                    curr_items.append(item+'\n')

    if curr_items:
        create_playlist(path, playlist_basename, curr_items)

    if too_long_items:
        print '\nThis files exceeded the given length and were not added to any playlist...\n'
        for i in too_long_items:
            print basename(i)

def create_playlist(path, playlist_basename, curr_items):
    global playlist_number, curr_length
    name = path + str(playlist_number) + '. ' + playlist_basename + str(int(curr_length/60)) + 'min' + '.m3u'
    playlist_file = open(name, 'w')
    playlist_file.writelines(curr_items)
    playlist_file.close()
    print 'Playlist generated, name: ', name , ' length ', curr_length/60 , 'min'
    playlist_number += 1
    curr_length = 0
    del curr_items[:]

def handleException(e):
    print type(e)     # the exception instance
    print e.args      # arguments stored in .args
    print e           # __str__ allows args to printed directly

if __name__ == '__main__':
    main()

Creating playlists

Its use is simple:

$ ./genPlayListByLength.py -h
usage: genPlayListByLength.py [-h] -d DIRECTORY -l LENGTH

Generate playlists with the indicated length

optional arguments:
  -h, --help            show this help message and exit
  -d DIRECTORY, --directory DIRECTORY
                        Directory with music files
  -l LENGTH, --length LENGTH
                        Length of the playlist, in minutes


[~/Desarrollo/WorkSpaces/Py_WorkSpace/GenPlayListByLenght/src]
$ ./genPlayListByLength.py -d /media/RAID_External/Music/EPIC/Nueva/ -l 20
Playlist generated, name:  ./playlists/genPlayListByLength.py20_1.m3u  length  24.0001451247 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_2.m3u  length  22.7172426304 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_3.m3u  length  24.2311836735 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_4.m3u  length  20.2354164777 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_5.m3u  length  21.8601359014 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_6.m3u  length  28.3070597128 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_7.m3u  length  22.7946424792 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_8.m3u  length  21.2017535903 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_9.m3u  length  21.7807044596 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_10.m3u  length  21.1862736206 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_11.m3u  length  23.5667059713 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_12.m3u  length  21.3402993197 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_13.m3u  length  25.1046409675 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_15.m3u  length  20.4145971277 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_16.m3u  length  21.0794618292 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_17.m3u  length  20.2702464097 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_18.m3u  length  21.2315525321 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_19.m3u  length  20.798403305 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_20.m3u  length  22.1189417989 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_21.m3u  length  21.7013696145 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_22.m3u  length  22.971888133 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_23.m3u  length  21.8250628874 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_25.m3u  length  21.3321723356 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_26.m3u  length  21.5465699169 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_27.m3u  length  24.9339743008 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_28.m3u  length  32.0853333333 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_29.m3u  length  25.4854482237 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_30.m3u  length  20.7996613757 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_31.m3u  length  21.3372033258 min
Playlist generated, name:  ./playlists/genPlayListByLength.py20_32.m3u  length  22.5926288738 min

The script will create as many playlists of the given length as it can, 32 above.

Improvements

It took me half an hour to write the script, so it can greatly be improved. Right now it only looks music files in the current directory, not recursively.

Contribute

If you want to improve it yourself, it hosted at GitHub.

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