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https://github.com/bastibe/python-soundfile

SoundFile is an audio library based on libsndfile, CFFI, and NumPy
https://github.com/bastibe/python-soundfile

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SoundFile is an audio library based on libsndfile, CFFI, and NumPy

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README 

        
python-soundfile

================



|version| |python| |status| |license|



|contributors| |downloads|



The `soundfile `__ module is an audio

library based on libsndfile, CFFI and NumPy. Full documentation is

available on https://python-soundfile.readthedocs.io/.



The ``soundfile`` module can read and write sound files. File reading/writing is

supported through `libsndfile `__,

which is a free, cross-platform, open-source (LGPL) library for reading

and writing many different sampled sound file formats that runs on many

platforms including Windows, OS X, and Unix. It is accessed through

`CFFI `__, which is a foreign function

interface for Python calling C code. CFFI is supported for CPython 2.6+,

3.x and PyPy 2.0+. The ``soundfile`` module represents audio data as NumPy arrays.



| python-soundfile is BSD licensed (BSD 3-Clause License).

| (c) 2013, Bastian Bechtold



|open-issues| |closed-issues| |open-prs| |closed-prs|



.. |contributors| image:: https://img.shields.io/github/contributors/bastibe/python-soundfile.svg

.. |version| image:: https://img.shields.io/pypi/v/soundfile.svg

.. |python| image:: https://img.shields.io/pypi/pyversions/soundfile.svg

.. |license| image:: https://img.shields.io/github/license/bastibe/python-soundfile.svg

.. |downloads| image:: https://img.shields.io/pypi/dm/soundfile.svg

.. |open-issues| image:: https://img.shields.io/github/issues/bastibe/python-soundfile.svg

.. |closed-issues| image:: https://img.shields.io/github/issues-closed/bastibe/python-soundfile.svg

.. |open-prs| image:: https://img.shields.io/github/issues-pr/bastibe/python-soundfile.svg

.. |closed-prs| image:: https://img.shields.io/github/issues-pr-closed/bastibe/python-soundfile.svg

.. |status| image:: https://img.shields.io/pypi/status/soundfile.svg



Breaking Changes

----------------



The ``soundfile`` module has evolved rapidly in the past. Most

notably, we changed the import name from ``import pysoundfile`` to

``import soundfile`` in 0.7. In 0.6, we cleaned up many small

inconsistencies, particularly in the the ordering and naming of

function arguments and the removal of the indexing interface.



In 0.8.0, we changed the default value of ``always_2d`` from ``True``

to ``False``. Also, the order of arguments of the ``write`` function

changed from ``write(data, file, ...)`` to ``write(file, data, ...)``.



In 0.9.0, we changed the ``ctype`` arguments of the ``buffer_*``

methods to ``dtype``, using the Numpy ``dtype`` notation. The old

``ctype`` arguments still work, but are now officially deprecated.



In 0.12.0, we changed the load order of the libsndfile library. Now,

the packaged libsndfile in the platform-specific wheels is tried

before falling back to any system-provided libsndfile. If you would

prefer using the system-provided libsndfile, install the source

package or source wheel instead of the platform-specific wheels.



Installation

------------



The ``soundfile`` module depends on the Python packages CFFI and NumPy, and the

library libsndfile.



In a modern Python, you can use ``pip install soundfile`` to download

and install the latest release of the ``soundfile`` module and its

dependencies. On Windows (64/32) and OS X (Intel/ARM) and Linux 64,

this will also install a current version of the library libsndfile. If

you install the source module, you need to install libsndfile using

your distribution's package manager, for example ``sudo apt install

libsndfile1``.



If you are running on an unusual platform or if you are using an older

version of Python, you might need to install NumPy and CFFI separately,

for example using the Anaconda_ package manager.



.. _Anaconda: https://www.continuum.io/downloads



Building

--------



``Soundfile`` itself does not contain any compiled code and can be

bundled into a wheel with the usual ``python setup.py bdist_wheel``.

However, ``soundfile`` relies on libsndfile, and optionally ships its

own copy of libsndfile in the wheel.



To build a binary wheel that contains libsndfile, make sure to

checkout and update the ``_soundfile_data`` submodule, then run

``python setup.py bdist_wheel`` as usual. If the resulting file size

of the wheel is around one megabyte, a matching libsndfile has been

bundled (without libsndfile, it's around 25 KB).



To build binary wheels for all supported platforms, run ``python

build_wheels.py``, which will ``python setup.py bdist_wheel`` for each

of the platforms we have precompiled libsndfiles for.



Error Reporting

---------------



In case of API usage errors the ``soundfile`` module raises the usual `ValueError` or `TypeError`.



For other errors `SoundFileError` is raised (used to be `RuntimeError`).

Particularly, a `LibsndfileError` subclass of this exception is raised on

errors reported by the libsndfile library. In that case the exception object

provides the libsndfile internal error code in the `LibsndfileError.code` attribute and the raw

libsndfile error message in the `LibsndfileError.error_string` attribute.



Read/Write Functions

--------------------



Data can be written to the file using `soundfile.write()`, or read from

the file using `soundfile.read()`. The ``soundfile`` module can open all file formats

that `libsndfile supports

`__, for example WAV,

FLAC, OGG and MAT files (see `Known Issues `__ below about writing OGG files).



Here is an example for a program that reads a wave file and copies it

into an FLAC file:



.. code:: python



    import soundfile as sf



    data, samplerate = sf.read('existing_file.wav')

    sf.write('new_file.flac', data, samplerate)



Block Processing

----------------



Sound files can also be read in short, optionally overlapping blocks

with `soundfile.blocks()`.

For example, this calculates the signal level for each block of a long

file:



.. code:: python



   import numpy as np

   import soundfile as sf



   rms = [np.sqrt(np.mean(block**2)) for block in

          sf.blocks('myfile.wav', blocksize=1024, overlap=512)]



``SoundFile`` Objects

---------------------



Sound files can also be opened as `SoundFile` objects. Every

`SoundFile` has a specific sample rate, data format and a set number of

channels.



If a file is opened, it is kept open for as long as the `SoundFile`

object exists. The file closes when the object is garbage collected,

but you should use the `SoundFile.close()` method or the

context manager to close the file explicitly:



.. code:: python



   import soundfile as sf



   with sf.SoundFile('myfile.wav', 'r+') as f:

       while f.tell() < f.frames:

           pos = f.tell()

           data = f.read(1024)

           f.seek(pos)

           f.write(data*2)



All data access uses frames as index. A frame is one discrete time-step

in the sound file. Every frame contains as many samples as there are

channels in the file.



RAW Files

---------



`soundfile.read()` can usually auto-detect the file type of sound files. This

is not possible for RAW files, though:



.. code:: python



   import soundfile as sf



   data, samplerate = sf.read('myfile.raw', channels=1, samplerate=44100,

                              subtype='FLOAT')



Note that on x86, this defaults to ``endian='LITTLE'``. If you are

reading big endian data (mostly old PowerPC/6800-based files), you

have to set ``endian='BIG'`` accordingly.



You can write RAW files in a similar way, but be advised that in most

cases, a more expressive format is better and should be used instead.



Virtual IO

----------



If you have an open file-like object, `soundfile.read()` can open it just like

regular files:



.. code:: python



    import soundfile as sf

    with open('filename.flac', 'rb') as f:

        data, samplerate = sf.read(f)



Here is an example using an HTTP request:



.. code:: python



    import io

    import soundfile as sf

    from urllib.request import urlopen



    url = "http://tinyurl.com/shepard-risset"

    data, samplerate = sf.read(io.BytesIO(urlopen(url).read()))



Note that the above example only works with Python 3.x.

For Python 2.x support, replace the third line with:



.. code:: python



    from urllib2 import urlopen



In-memory files

^^^^^^^^^^^^^^^



Chunks of audio, i.e. `bytes`, can also be read and written without touching the filesystem.

In the following example OGG is converted to WAV entirely in memory (without writing files to the disk):



.. code:: python



    import io

    import soundfile as sf



    def ogg2wav(ogg: bytes):

        ogg_buf = io.BytesIO(ogg)

        ogg_buf.name = 'file.ogg'

        data, samplerate = sf.read(ogg_buf)

        wav_buf = io.BytesIO()

        wav_buf.name = 'file.wav'

        sf.write(wav_buf, data, samplerate)

        wav_buf.seek(0)  # Necessary for `.read()` to return all bytes

        return wav_buf.read()



Known Issues

------------



Writing to OGG files can result in empty files with certain versions of libsndfile. See `#130 `__ for news on this issue.



If using a Buildroot style system, Python has trouble locating ``libsndfile.so`` file, which causes python-soundfile to not be loaded. This is apparently a bug in `python `__. For the time being, in ``soundfile.py``, you can remove the call to ``_find_library`` and hardcode the location of the ``libsndfile.so`` in ``_ffi.dlopen``. See `#258 `__ for discussion on this issue.



News

----



2013-08-27 V0.1.0 Bastian Bechtold:

    Initial prototype. A simple wrapper for libsndfile in Python



2013-08-30 V0.2.0 Bastian Bechtold:

    Bugfixes and more consistency with PySoundCard



2013-08-30 V0.2.1 Bastian Bechtold:

    Bugfixes



2013-09-27 V0.3.0 Bastian Bechtold:

    Added binary installer for Windows, and context manager



2013-11-06 V0.3.1 Bastian Bechtold:

    Switched from distutils to setuptools for easier installation



2013-11-29 V0.4.0 Bastian Bechtold:

    Thanks to David Blewett, now with Virtual IO!



2013-12-08 V0.4.1 Bastian Bechtold:

    Thanks to Xidorn Quan, FLAC files are not float32 any more.



2014-02-26 V0.5.0 Bastian Bechtold:

    Thanks to Matthias Geier, improved seeking and a flush() method.



2015-01-19 V0.6.0 Bastian Bechtold:

    A big, big thank you to Matthias Geier, who did most of the work!



    - Switched to ``float64`` as default data type.

    - Function arguments changed for consistency.

    - Added unit tests.

    - Added global `read()`, `write()`, `blocks()` convenience

      functions.

    - Documentation overhaul and hosting on readthedocs.

    - Added ``'x'`` open mode.

    - Added `tell()` method.

    - Added ``__repr__()`` method.



2015-04-12 V0.7.0 Bastian Bechtold:

    Again, thanks to Matthias Geier for all of his hard work, but also

    Nils Werner and Whistler7 for their many suggestions and help.



    - Renamed ``import pysoundfile`` to ``import soundfile``.

    - Installation through pip wheels that contain the necessary

      libraries for OS X and Windows.

    - Removed ``exclusive_creation`` argument to `write()`.

    - Added `truncate()` method.



2015-10-20 V0.8.0 Bastian Bechtold:

    Again, Matthias Geier contributed a whole lot of hard work to this

    release.



    - Changed the default value of ``always_2d`` from ``True`` to

      ``False``.

    - Numpy is now optional, and only loaded for ``read`` and

      ``write``.

    - Added `SoundFile.buffer_read()` and

      `SoundFile.buffer_read_into()` and `SoundFile.buffer_write()`,

      which read/write raw data without involving Numpy.

    - Added `info()` function that returns metadata of a sound file.

    - Changed the argument order of the `write()` function from

      ``write(data, file, ...)`` to ``write(file, data, ...)``



    And many more minor bug fixes.



2017-02-02 V0.9.0 Bastian Bechtold:

    Thank you, Matthias Geier, Tomas Garcia, and Todd, for contributions

    for this release.



    - Adds support for ALAC files.

    - Adds new member ``__libsndfile_version__``

    - Adds number of frames to ``info`` class

    - Adds ``dtype`` argument to ``buffer_*`` methods

    - Deprecates ``ctype`` argument to ``buffer_*`` methods

    - Adds official support for Python 3.6



    And some minor bug fixes.



2017-11-12 V0.10.0 Bastian Bechtold:

    Thank you, Matthias Geier, Toni Barth, Jon Peirce, Till Hoffmann,

    and Tomas Garcia, for contributions to this release.



    - Should now work with cx_freeze.

    - Several documentation fixes in the README.

    - Removes deprecated ``ctype`` argument in favor of ``dtype`` in ``buffer_*()``.

    - Adds `SoundFile.frames` in favor of now-deprecated ``__len__()``.

    - Improves performance of `blocks()` and `SoundFile.blocks()`.

    - Improves import time by using CFFI's out of line mode.

    - Adds a build script for building distributions.



2022-06-02 V0.11.0 Bastian Bechtold:

    Thank you, tennies, Hannes Helmholz, Christoph Boeddeker, Matt

    Vollrath, Matthias Geier, Jacek Konieczny, Boris Verkhovskiy,

    Jonas Haag, Eduardo Moguillansky, Panos Laganakos, Jarvy Jarvison,

    Domingo Ramirez, Tim Chagnon, Kyle Benesch, Fabian-Robert Stöter,

    Joe Todd



    - MP3 support

    - Adds binary wheels for macOS M1

    - Improves compatibility with macOS, specifically for M1 machines

    - Fixes file descriptor open for binary wheels on Windows and Python 3.5+

    - Updates libsndfile to v1.1.0

    - Adds get_strings method for retrieving all metadata at once

    - Improves documentation, error messages and tests

    - Displays length of very short files in samples

    - Supports the file system path protocol (pathlib et al)



2023-02-02 V0.12.0 Bastian Bechtold

    Thank you, Barabazs, Andrew Murray, Jon Peirce, for contributions

    to this release.



    - Updated libsndfile to v1.2.0

    - Improves precompiled library location, especially with py2app or cx-freeze.

    - Now provide binary wheels for Linux x86_64

    - Now prefers packaged libsndfile over system-installed libsndfile



2023-02-15 V0.12.1 Bastian Bechtold

    Thank you, funnypig, for the bug report



    - Fixed typo on library location detection if no packaged lib and

      no system lib was found