A Python wrapper for the high-quality vocoder "World"





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PyWORLD - A Python wrapper of WORLD Vocoder

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WORLD Vocoder is a fast and high-quality vocoder which parameterizes speech into three components:

  1. f0: Pitch contour
  2. sp: Harmonic spectral envelope
  3. ap: Aperiodic spectral envelope (relative to the harmonic spectral envelope)

It can also (re)synthesize speech using these features (see examples below).

For more information, please visit Dr. Morise's WORLD repository and the official website of WORLD Vocoder


Vocoder Functions

import pyworld as pw
_f0, t = pw.dio(x, fs)    # raw pitch extractor
f0 = pw.stonemask(x, _f0, t, fs)  # pitch refinement
sp = pw.cheaptrick(x, f0, t, fs)  # extract smoothed spectrogram
ap = pw.d4c(x, f0, t, fs)         # extract aperiodicity

y = pw.synthesize(f0, sp, ap, fs) # synthesize an utterance using the parameters


# Convert speech into features (using default arguments)
f0, sp, ap = pw.wav2world(x, fs)

You can change the default arguments of the function, too. See more info using help.


Using Pip

pip install pyworld

Building from Source

git clone
cd Python-Wrapper-for-World-Vocoder
git submodule update --init
pip install -U pip
pip install -r requirements.txt
pip install .

It will automatically git clone Morise's World Vocoder (C++ version).
(It seems to me that using virtualenv or conda is the best practice.)

Installation Validation

You can validate installation by running

cd demo

to see if you get results in test/ direcotry. (Please avoid writing and executing codes in the Python-Wrapper-for-World-Vocoder folder for now.)


  • Operating systems
    • Linux Ubuntu 14.04+
    • Windows (thanks to wuaalb)
    • WSL
  • Python
    • 2.7 (Windows is currently not supported)
    • 3.7/3.6/3.5

You can install dependencies these by pip install -r requirements.txt


  • WORLD vocoder is designed for speech sampled ≥ 16 kHz. Applying WORLD to 8 kHz speech will fail. See a possible workaround here.
  • When the SNR is low, extracting pitch using harvest instead of dio is a better option.


  1. Upgrade your Cython version to 0.24.
    (I failed to build it on Cython 0.20.1post0)
    It'll require you to download Cython form
    Unzip it, and python install it.
    (I tried pip install Cython but the upgrade didn't seem correct)
    (Again, add --user if you don't have root access.)

  2. Upon executing demo/, the following code might be needed in some environments (e.g. when you're working on a remote Linux server):

    import matplotlib
  3. If you encounter library not found: sndfile error upon executing,
    you might have to install it by apt-get install libsoundfile1.
    You can also replace pysoundfile with scipy or librosa, but some modification is needed:

    • librosa:
      • load(fiilename, dtype=np.float64)
      • output.write_wav(filename, wav, fs)
      • remember to pass dtype argument to ensure that the method gives you a double.
    • scipy:
      • You'll have to write a customized utility function based on the following methods
      • (but this gives you short)
  4. If you have installation issue on Windows, I probably could not provide much help because my development environment is Ubuntu and Windows Subsystem for Linux (read this if you are interested in installing it).

Other Installation Suggestions

  1. Use pip install . is safer and you can easily uninstall pyworld by pip uninstall pyworld
  • For Mac users: You might need to do MACOSX_DEPLOYMENT_TARGET=10.9 pip install . See issue.
  1. Another way to install pyworld is via
    python install
    • Add --user if you don't have root access
    • Add --record install.txt to track the installation dir
  2. If you just want to try out some experiments, execute
    python build_ext --inplace
    Then you can use PyWorld from this directory.
    You can also copy the resulting (pyworld.{arch}.pyd on Windows) file to ~/.local/lib/python2.7/site-packages (or corresponding Windows directory) so that you can use it everywhere like an installed package.
    Alternatively you can copy/symlink the compiled files using pip, e.g. pip install -e .


Thank all contributors (tats-u, wuaalb, r9y9, rikrd, kudan2510) for making this repo better and sotelo whose inspired this repo.

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