audioread 1.0.2

multi-library, cross-platform audio decoding

Decode audio files using whichever backend is available. The library currently supports:

• Gstreamer via gst-python.

• Core Audio on Mac OS X via ctypes. (PyObjC not required.)

• MAD via the pymad bindings.

• FFmpeg via its command-line interface.

• The standard library wave and aifc modules (for WAV and AIFF files).

Use the library like so:

with audioread.audio_open(filename) as f:
    print(f.channels, f.samplerate, f.duration)
    for buf in f:
        do_something(buf)

Buffers in the file can be accessed by iterating over the object returned from audio_open. Each buffer is a buffer or str object containing raw 16-bit little-endian signed integer PCM data. (Currently, these PCM format parameters are not configurable, but this could be added to most of the backends.)

Additional values are available as fields on the audio file object:

• channels is the number of audio channels (an integer).

• samplerate is given in Hz (an integer).

• duration is the length of the audio in seconds (a float).

The audio_open function transparently selects a backend that can read the file. (Each backend is implemented in a module inside the audioread package.) If no backends succeed in opening the file, a DecodeError exception is raised. This exception is only used when the file type is unsupported by the backends; if the file doesn’t exist, a standard IOError will be raised.

Audioread is “universal” and supports both Python 2 (2.6+) and Python 3 (3.2+). The GStreamer backend currently only supports 2.x since gst-python is 2.x-only.

Future Work

Possible additional backends:

• PyOgg?

• Other command-line tools?

Example

The included decode.py script demonstrates using this package to convert compressed audio files to WAV files.

Version History

1.0.2

Send SIGKILL, not SIGTERM, to ffmpeg processes to avoid occasional hangs.

1.0.1

When GStreamer fails to report a duration, raise an exception instead of silently setting the duration field to None.

1.0.0

Catch GStreamer’s exception when necessary components, such as uridecodebin, are missing. The GStreamer backend now accepts relative paths. Fix a hang in GStreamer when the stream finishes before it begins (when reading broken files). Initial support for Python 3.

0.8

All decoding errors are now subclasses of DecodeError.

0.7

Fix opening WAV and AIFF files via Unicode filenames.

0.6

Make FFmpeg timeout more robust. Dump FFmpeg output on timeout. Fix a nondeterministic hang in the Gstreamer backend. Fix a file descriptor leak in the MAD backend.

0.5

Fix crash when FFmpeg fails to report a duration. Fix a hang when FFmpeg fills up its stderr output buffer. Add a timeout to ffmpeg tool execution (currently 10 seconds for each 4096-byte read); a ReadTimeoutError exception is raised if the tool times out.

0.4

Fix channel count detection for FFmpeg backend.

0.3

Fix a problem with the Gstreamer backend where audio files could be left open even after the GstAudioFile was “closed”.

0.2

Fix a hang in the GStreamer backend that occurs occasionally on some platforms.

0.1

Initial release.

Et Cetera

audioread is by Adrian Sampson. It is made available under the MIT license. An alternative to this module is decoder.py.