Pydub
Pydub lets you do stuff to audio in a way that isn't stupid.
Quickstart
Open a WAV file
from pydub import AudioSegment
song = AudioSegment.from_wav("never_gonna_give_you_up.wav")
...or a mp3
song = AudioSegment.from_mp3("never_gonna_give_you_up.mp3")
... or an ogg, or flv, or anything else ffmpeg supports
ogg_version = AudioSegment.from_ogg("never_gonna_give_you_up.ogg")
flv_version = AudioSegment.from_flv("never_gonna_give_you_up.flv")
mp4_version = AudioSegment.from_file("never_gonna_give_you_up.mp4", "mp4")
wma_version = AudioSegment.from_file("never_gonna_give_you_up.wma", "wma")
aac_version = AudioSegment.from_file("never_gonna_give_you_up.aiff", "aac")
Slice audio:
# pydub does things in milliseconds
ten_seconds = 10 * 1000
first_10_seconds = song[:ten_seconds]
last_5_seconds = song[-5000:]
Make the beginning louder and the end quieter
# boost volume by 6dB
beginning = first_10_seconds + 6
# reduce volume by 3dB
end = last_5_seconds - 3
Concatenate audio (add one file to the end of another)
without_the_middle = beginning + end
How long is it?
without_the_middle.duration_seconds == 15.0
AudioSegments are immutable
# song is not modified
backwards = song.reverse()
Crossfade (again, beginning and end are not modified)
# 1.5 second crossfade
with_style = beginning.append(end, crossfade=1500)
Repeat
# repeat the clip twice
do_it_over = with_style * 2
Fade (note that you can chain operations because everything returns
an AudioSegment)
# 2 sec fade in, 3 sec fade out
awesome = do_it_over.fade_in(2000).fade_out(3000)
Save the results (again whatever ffmpeg supports)
awesome.export("mashup.mp3", format="mp3")
Save the results with tags (metadata)
awesome.export("mashup.mp3", format="mp3", tags={'artist': 'Various artists', 'album': 'Best of 2011', 'comments': 'This album is awesome!'})
You can pass an optional bitrate argument to export using any syntax ffmpeg
supports.
awesome.export("mashup.mp3", format="mp3", bitrate="192k")
Any further arguments supported by ffmpeg can be passed as a list in a
'parameters' argument, with switch first, argument second. Note that no
validation takes place on these parameters, and you may be limited by what
your particular build of ffmpeg/avlib supports.
# Use preset mp3 quality 0 (equivalent to lame V0)
awesome.export("mashup.mp3", format="mp3", parameters=["-q:a", "0"])
# Mix down to two channels and set hard output volume
awesome.export("mashup.mp3", format="mp3", parameters=["-ac", "2", "-vol", "150"])
Debugging
Most issues people run into are related to converting between formats using
ffmpeg/avlib. Pydub provides a logger that outputs the subprocess calls to
help you track down issues:
>>> import logging
>>> l = logging.getLogger("pydub.converter")
>>> l.setLevel(logging.DEBUG)
>>> l.addHandler(logging.StreamHandler())
>>> AudioSegment.from_file("./test/data/test1.mp3")
subprocess.call(['ffmpeg', '-y', '-i', '/var/folders/71/42k8g72x4pq09tfp920d033r0000gn/T/tmpeZTgMy', '-vn', '-f', 'wav', '/var/folders/71/42k8g72x4pq09tfp920d033r0000gn/T/tmpK5aLcZ'])
<pydub.audio_segment.AudioSegment object at 0x101b43e10>
Don't worry about the temporary files used in the conversion. They're cleaned up
automatically.
Bugs & Questions
You can file bugs in our github issues tracker,
and ask any technical questions on
Stack Overflow using the pydub tag.
We keep an eye on both.
Installation
Installing pydub is easy, but don't forget to install ffmpeg/avlib (the next section in this doc)
pip install pydub
Or install the latest dev version from github (or replace @master with a release version like @v0.12.0)…
pip install git+https://github.com/jiaaro/pydub.git@master
-OR-
git clone https://github.com/jiaaro/pydub.git
-OR-
Copy the pydub directory into your python path. Zip
here
Dependencies
You can open and save WAV files with pure python. For opening and saving non-wav
files – like mp3 – you'll need ffmpeg or
libav.
Getting ffmpeg set up
You may use libav or ffmpeg.
Mac (using homebrew):
# libav
brew install libav --with-libvorbis --with-sdl --with-theora
#### OR #####
# ffmpeg
brew install ffmpeg --with-libvorbis --with-sdl2 --with-theora
Linux (using aptitude):
# libav
apt-get install libav-tools libavcodec-extra-53
#### OR #####
# ffmpeg
apt-get install ffmpeg libavcodec-extra-53
Windows:
- Download and extract libav from Windows binaries provided here.
- Add the libav
/binfolder to your PATH envvar pip install pydub
Important Notes
AudioSegment objects are immutable
Ogg exporting and default codecs
The Ogg specification (http://tools.ietf.org/html/rfc5334) does not specify
the codec to use, this choice is left up to the user. Vorbis and Theora are just
some of a number of potential codecs (see page 3 of the rfc) that can be used for the
encapsulated data.
When no codec is specified exporting to ogg will default to using vorbis
as a convinence. That is:
from pydub import AudioSegment
song = AudioSegment.from_mp3("test/data/test1.mp3")
song.export("out.ogg", format="ogg") # Is the same as:
song.export("out.ogg", format="ogg", codec="libvorbis")
Example Use
Suppose you have a directory filled with mp4 and flv videos and you want to convert all of them to mp3 so you can listen to them on your mp3 player.
import os
import glob
from pydub import AudioSegment
video_dir = '/home/johndoe/downloaded_videos/' # Path where the videos are located
extension_list = ('*.mp4', '*.flv')
os.chdir(video_dir)
for extension in extension_list:
for video in glob.glob(extension):
mp3_filename = os.path.splitext(os.path.basename(video))[0] + '.mp3'
AudioSegment.from_file(video).export(mp3_filename, format='mp3')
How about another example?
from glob import glob
from pydub import AudioSegment
playlist_songs = [AudioSegment.from_mp3(mp3_file) for mp3_file in glob("*.mp3")]
first_song = playlist_songs.pop(0)
# let's just include the first 30 seconds of the first song (slicing
# is done by milliseconds)
beginning_of_song = first_song[:30*1000]
playlist = beginning_of_song
for song in playlist_songs:
# We don't want an abrupt stop at the end, so let's do a 10 second crossfades
playlist = playlist.append(song, crossfade=(10 * 1000))
# let's fade out the end of the last song
playlist = playlist.fade_out(30)
# hmm I wonder how long it is... ( len(audio_segment) returns milliseconds )
playlist_length = len(playlist) / (1000*60)
# lets save it!
out_f = open("%s_minute_playlist.mp3" % playlist_length, 'wb')
playlist.export(out_f, format='mp3')
