Manipulate audio with a simple Python library

http://pydub.com/

by coppolaemilio • 12 years ago

164 43 12 years ago

pydub.com

r0muald• 12 years ago

last_5_seconds = song[5000:]

I think it should be song[-5000:]

EDIT it was already reported https://github.com/jiaaro/pydub/issues/65

jiaaro5• 12 years ago

oh damn, updated the readme but not the dot-com.

Fixed. I really need to automate that :/

meowface4• 12 years ago

This looks really cool.

I'm a Python developer but have a little experience with audio/music processing. Is there some other software or DSL that can manipulate audio files with a high-level syntax like this?

acbart• 12 years ago

It reminds me of VirtualDub's scripting language, which is meant for videos but could do audio, if I recall correctly. It's been about half a decade since I used it, though...

meowface4• 12 years ago

What do professional music producers and mixers use? I imagine GUI-type mixing software is still the most popular, but I feel like there must be some experimental musicians out there producing music by fuzzing different parameters in some kind of scripting or configuration language.

If there actually aren't, I kind of feel like there should be.

xj9• 12 years ago

I don't know if this fits the bill exactly, but I've been dying to have time to play around with Overtone[1] and Emacs Live[2]!

[1] http://overtone.github.io [2]: http://overtone.github.io/emacs-live/

crucialfelix• 12 years ago

http://supercollider.github.io/ is one of the most widely used.

rhizome31• 12 years ago

There's ChucK http://chuck.cs.princeton.edu/ and also for Python there's Pyo http://ajaxsoundstudio.com/software/pyo/

goldfeld• 12 years ago

I'd be crazy for a library (any language) to distill a sound file into discrete MIDI notes (or any notation), with configurable threshold levels. Clustering those into different tracks by some unsupervised learning would be a dream.

lifeisstillgood3• 12 years ago

This comment is mostly why I have never tread in the feared world of multimedia. I simply don't understand what it means. I mean I can guess at trying to pull the original "tracks" "laid down" out from a recording but - is that possible, common but not FOSS?

I simply don't know where to start and have not had the incentive to discover. It's probably as laughable to others as say someone turnin up and saying "yeah SQL - I sort of understand it's to do with tables right?" But audio and video seem like closed worlds of programming. There seems to be no gateway from here to there.

So something like this is v exciting - it might be the gateway drug.

jfb2• 12 years ago

Audio and video really aren't that closed; they just require a commitment to learning things that are pretty different than what a typical programmer does; and they get math heavy. But they're really, really fun to play with, when you knuckle down, and there's a fairly gentle learning curve from understanding formats and containers to samples to statistical signal processing and psychoacoustic and visual models.

And being good at it means writing your own ticket, if you're a careerist.

chestervonwinch• 12 years ago

Ableton Live's most recent version has this feature. It's called harmony to midi, and it's pretty cool (Ableton is a fantastic program in general).

I'm not aware of any open libs for this task though. I'm not really sure how you would go about this either. Something with wavelets would be my first guess? There is a wavelet lib for python [0]. You'd have to determine the correspondence between wavelet scale and midi note frequency.

This assumes audio tracks are separated. Separating mixed tracks seems like an even bigger can of worms.

[0] http://www.pybytes.com/pywavelets/

cannam2• 12 years ago

If what you're talking about is starting from an audio mix and estimating the complete set of notes that produced it, you could try Silvet (http://code.soundsoftware.ac.uk/projects/silvet), a (C++) implementation of a polyphonic note estimator from audio.

It's realised as a Vamp plugin which you can run in a host like Sonic Visualiser to review the results, play them back, and export as MIDI. (I'm involved with both projects.)

The general shape of this method, and of many related methods, is:

* convert audio to a time-frequency representation using some variation on the short-time Fourier transform

* match each time step of the time-frequency grid against a set of templates extracted from frequency profiles of various instruments, using some statistical approximation technique

* take the resulting pitch probability distributions and estimate what note objects they might correspond to, using simple thresholding (as in Silvet) or a Markov model for note transitions etc

Silvet is a useful and interesting implementation, but if you try it, you'll also learn the limitations of current methods when used against complete musical mixes. (Some of this is intrinsic to the problem -- the information might not be there, and humans can't always transcribe it either.)

Joeboy2• 12 years ago

I've heard Melodyne solves this problem very successfully, and the demos look impressive. Any idea what it's doing? Is it patented / secret / witchcraft? Or just has more templates?

Joeboy2• 12 years ago

A couple of things that people who like this might also be interested in:

Coursera.org is currently running a course called "Audio Signal Processing for Music Applications" which I believe uses python. It's in its second week, so you have time to catch up. https://www.coursera.org/course/audio

http://aubio.org/ is a library that does note onset detection, pitch detection, beat / tempo tracking and various other things. It has python bindings.

urs2102• 12 years ago

What is the best way to break apart an MP3 file (similar to ID3Lib) so you can see how it's encoded and edit the artist name, song name, add an image, change the encoding format, etc?

Is there a good python library for re-encoding an MP3?

jiaaro5• 12 years ago

pydub does it, but it shells out to ffmpeg, not sure if that's acceptable

jpasden• 12 years ago

This might do what you're looking for:

http://eyed3.nicfit.net/

emillon2• 12 years ago

I've been similarly frustrated with DAWs too. In the last few weeks I had a go at writing a DSL that shells out to SoX for audio manipulation. This way I don't have to manipulate audio samples myself.

It's way less polished than pydub but here it is if anyone is interested:

https://github.com/emillon/tmc

Example:

https://github.com/emillon/tmc/blob/master/Music/TMC/Example...

At first it was a pretext to play with free monads, a way of building EDSLs. But right now I'm not sure it's not just a complication. Though, having an intermediate representation before executing the SoX commands makes it possible to write an optimizer (for example, collapsing two audio shifts).

jiaaro5• 12 years ago

I was thinking of using sox as well - turns out a lot a lot of the audioop module in the Stdlib comes directly from sox :)

relevant comment in the audioop source: https://github.com/python-git/python/blob/master/Modules/aud...

conradfr• 12 years ago

I know it's not available on Linux and not free but have you tried Reaper ? It has lots of scripting / coding capabilities.

emillon2• 12 years ago

Interesting, I didn't know about these capabilities, thanks!

prezjordan• 12 years ago

Cool idea! I like the overloaded operators.

mobiuscog• 12 years ago

I would if they were consistent, but having some to change volume and some to change repeats is somewhat jarring.

jiaaro5• 12 years ago

I almost used a decibel type but in practice, when you write

    my_sound + 6

it feels pretty natural to think about that as "add 6dB" and

    my_sound * 3

as "my_sound 3 times"

Also, since those are the only odd overloads, it is quite easy to learn (at least I think so, but I'm the author =P )

stevetjoa• 12 years ago

Thanks for making this.

Relevant plug: I have a Vagrant box [1] and GitHub repo [2] containing IPython notebooks that we use in a workshop on music information retrieval. (Caution: the IPython notebooks are under heavy development, i.e. incomplete. If you have any feedback, please create a GitHub issue.) I just added pydub to the latest version of the Vagrant box [3].

The nice thing about this setup is that, regardless of your host OS, everybody has the same development environment so you don't have to go through the pains of installing numpy, scipy, scikit-learn, essentia, and more.

[1] https://vagrantcloud.com/stevetjoa/boxes/stanford-mir

[2] https://github.com/stevetjoa/stanford-mir

[3] https://vagrantcloud.com/stevetjoa/boxes/stanford-mir/versio...

jiaaro5• 12 years ago

You're welcome :)

Looks like a cool project!

tdicola• 12 years ago

Nice! I love little focused Python libraries like this. Will have to keep it in mind if I ever do audio stuff in the future.

bravura• 12 years ago

Cool project.

The echonest remix API has similar capabilities, and can quantize into granularities of measures, beats, tatums.

http://echonest.github.io/remix/

jestinjoy1• 12 years ago

Suggestions on some cool academic projects that could use this library?

DarkIye• 12 years ago

I started writing a sample-level audio suite in Java, for musical purposes:

https://github.com/williamberg/audioDCB

which I'll probably discard because Java is not the right tool for the job. Inspecting pydub/pydub/pyaudioop.py , I see there are methods for working on the sample level. I'll make a mental note to come back to this project when I get back on the computer music bandwagon again.

Manipulate audio with a simple Python library

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