commit 8abf06be introduced a pause() prior to draining, in an attempt
to work around clearly broken pulseaudio client behavior for capture
streams (drain() is supposed to imply a stop).
but as the workaround was also applied to playback streams, it would
cause nasty "clicks", as the stream would (obviously) stop before being
resumed for draining.
but draining is actually pointless for capture streams, as we're closing
right afterwards, so the samples are lost anyway.
what's more, destructors are not supposed to wait for anything, so
draining in alsapcm_dealloc() was wrong to start with. so we remove it.
note that this is a minor behavior change, which is reflected by the
adjustment of the playback test to have an explicit close() at the end.
finally, close() was also affected by the pulseaudio bug (which was not
addressed before), so there we make draining exclusive to playback
streams.
PyAlsaAudio
For documentation, see http://larsimmisch.github.io/pyalsaaudio/
Author: Casper Wilstrup (cwi@aves.dk)
Maintainer: Lars Immisch (lars@ibp.de)
This package contains wrappers for accessing the ALSA API from Python. It is currently fairly complete for PCM devices, and has some support for mixers.
If you find bugs in the wrappers please open an issue in the issue tracker. Please don't send bug reports regarding ALSA specifically. There are several bugs in the ALSA API, and those should be reported to the ALSA team - not me.
This software is licensed under the PSF license - the same one used by the majority of the python distribution. Basically you can use it for anything you wish (even commercial purposes). There is no warranty whatsoever.
Installation
PyPI
To install pyalsaaudio via pip (or easy_install):
$ pip install pyalsaaudio
Manual installation
Note: the wrappers need a kernel with ALSA support, and the ALSA library and headers. The installation of these varies from distribution to distribution.
On Debian or Ubuntu, make sure to install libasound2-dev. On Arch,
install alsa-lib. When in doubt, search your distribution for a
package that contains libasound.so and asoundlib.h.
First, get the sources and change to the source directory:
$ git clone https://github.com/larsimmisch/pyalsaaudio.git
$ cd pyalsaaudio
Then, build:
$ python setup.py build
And install:
$ sudo python setup.py install
Using the API
The API documentation is included in the doc subdirectory of the source distribution; it is also online on http://larsimmisch.github.io/pyalsaaudio/.
There are some example programs included with the source:
- playwav.py plays back a wav file
- playbacktest.py plays back raw sound data read from stdin
- recordtest.py captures sound from the microphone and writes it raw to stdout.
- mixertest.py can be used to manipulate the mixers.