Setup PCM device in constructor.

.gitignore

@@ -4,11 +4,6 @@ MANIFEST
 doc/gh-pages/
 doc/html/
 doc/doctrees/
-doc/_build/
 gh-pages/
 build/
-dist/
-.vscode/
-/__pycache__/
-/pyalsaaudio.egg-info/
-*.raw
+dist/

CHANGES

@@ -0,0 +1,99 @@
+Version 0.8.6:
+- Added four methods to the 'PCM' class to allow users to get detailed information about the device:
+
+  - 'getformats()' returns a dictionary of name / value pairs, one for each of the card's
+    supported formats - e.g. '{"U8": 1, "S16_LE": 2}',
+  - 'getchannels()' returns a list of the supported channel numbers, e.g. '[1, 2]',
+  - 'getrates()' returns supported sample rates for the device, e.g. '[48000]',
+  - 'getratebounds()' returns the device's official minimum and maximum supported 
+    sample rates as a tuple, e.g. '(4000, 48000)'.
+  
+  (#82 contributed by @jdstmporter)
+
+- Prevent hang on close after capturing audio (#80 contributed by @daym)
+
+Version 0.8.5:
+- Return an empty string/bytestring when 'read()' detects an 
+  overrun. Previously the returned data was undefined (contributed by @jcea)
+
+- Unlimited setperiod buffer size when reading frames (contributed by @jcea)
+
+Version 0.8.4:
+- Fix Python3 API usage broken in 0.8.3
+
+Version 0.8.3:
+- Add DSD sample formats (contributed by @lintweaker)
+- Add Mixer.handleevents() to acknowledge events identified by select.poll (contributed by @PaulSD)
+- Add functions for listing cards and their names (contributed by @chrisdiamand)
+- Add a method for setting enums (contributed by @chrisdiamand)
+
+Version 0.8.2:
+- fix #3 (we cannot get the revision from git for pip installs)
+
+Version 0.8.1:
+- document changes (this file)
+
+Version 0.8:
+- 'PCM()' has new 'device' and 'cardindex' keyword arguments.
+
+  The keyword 'device' allows to select virtual devices, 'cardindex' can be
+  used to select hardware cards by index (as with 'mixers()' and 'Mixer()').
+
+  The 'card' keyword argument is still supported, but deprecated.
+
+  The reason for this change is that the 'card' keyword argument guessed
+  a device name from the card name, but this only works sometimes, and breaks
+  opening virtual devices.
+
+- new function 'pcms()' to list available PCM devices.
+
+- mixers() and Mixer() take an additional 'device' keyword argument.
+  This allows to list or open virtual devices.
+
+- The default behaviour of Mixer() without any arguments has changed.
+  Now Mixer() will try to open the 'default' Mixer instead of the Mixer
+  that is associated with card 0.
+
+- fix a memory leak under Python 3.x
+
+- some more memory leaks in error conditions fixed.
+
+Version 0.7:
+- fixed several memory leaks (patch 3372909), contributed by Erik Kulyk)
+
+
+Version 0.6:
+- mostly reverted patch 2594366: alsapcm_setup did not do complete error
+checking for good reasons; some ALSA functions in alsapcm_setup may fail without
+rendering the device unusable
+
+
+Version 0.5:
+- applied patch 2777035: Fixed setrec method in alsaaudio.c
+  This included a mixertest with more features
+- fixed/applied patch 2594366: alsapcm_setup does not do any error checking
+
+
+Version 0.4:
+- API changes: mixers() and Mixer() now take a card index instead of a
+  card name as optional parameter.
+- Support for Python 3.0
+- Documentation converted to reStructuredText; use Sphinx instead of LaTeX.
+- added cards()
+- added PCM.close()
+- added Mixer.close()
+- added mixer.getenum()
+
+
+Version 0.3:
+- wrapped blocking calls with Py_BEGIN_ALLOW_THREADS/Py_END_ALLOW_THREADS
+- added pause
+
+
+Version 0.2:
+- Many bugfixes related to playback in particular
+- Module documentation in the doc subdirectory
+
+
+Version 0.1:
+- Initial version

CHANGES.md

@@ -1,116 +0,0 @@
-# Version 0.10.1
-- restore previous xrun behaviour, #131
-- type hints
-
-# Version 0.10.0
-- assorted improvements (#123 from @ossilator)
-  - support for `periods` in the `PCM` constructor.
-  - new functions `PCM.state()`, `PCM.drop()` and `PCM.drain()`
-  - improved underrun/overrun handling
-  - documentation improvements/consolidation (docstrings were removed in favour of online documentation)
-  - more sampling rates
-  - bug fixes
-
-# Version 0.9.2
-- Fix alsamixer_getvolume (#112 from @stephensp)
-
-# Version 0.9.1:
-- Support decibel, percentage, and raw volumes in getvolume, setvolume, and getrange (#109 from @chrisdiamand)
-
-# Version 0.9.0:
-- Added keyword arguments for channels, format, rate and periodsize
-- Deprecated `setchannel`, `setformat`, `setrate` and `setperiodsize`
-
-# Version 0.8.6:
-- Added four methods to the `PCM` class to allow users to get detailed information about the device:
-
-  - `getformats()` returns a dictionary of name / value pairs, one for each of the card's
-    supported formats - e.g. `{"U8": 1, "S16_LE": 2}`,
-  - `getchannels()` returns a list of the supported channel numbers, e.g. `[1, 2]`,
-  - `getrates()` returns supported sample rates for the device, e.g. `[48000]`,
-  - `getratebounds()` returns the device's official minimum and maximum supported
-    sample rates as a tuple, e.g. `(4000, 48000)`.
-
-  (#82 contributed by @jdstmporter)
-
-- Prevent hang on close after capturing audio (#80 contributed by @daym)
-
-# Version 0.8.5:
-- Return an empty string/bytestring when `read()` detects an
-  overrun. Previously the returned data was undefined (contributed by @jcea)
-
-- Unlimited setperiod buffer size when reading frames (contributed by @jcea)
-
-# Version 0.8.4:
-- Fix Python3 API usage broken in 0.8.3
-
-# Version 0.8.3:
-- Add DSD sample formats (contributed by @lintweaker)
-- Add Mixer.handleevents() to acknowledge events identified by select.poll (contributed by @PaulSD)
-- Add functions for listing cards and their names (contributed by @chrisdiamand)
-- Add a method for setting enums (contributed by @chrisdiamand)
-
-# Version 0.8.2:
-- fix #3 (we cannot get the revision from git for pip installs)
-
-# Version 0.8.1:
-- document changes (this file)
-
-# Version 0.8:
-- `PCM()` has new `device` and `cardindex` keyword arguments.
-
-  The keyword `device` allows to select virtual devices, `cardindex` can be
-  used to select hardware cards by index (as with `mixers()` and `Mixer()`).
-
-  The `card` keyword argument is still supported, but deprecated.
-
-  The reason for this change is that the `card` keyword argument guessed
-  a device name from the card name, but this only works sometimes, and breaks
-  opening virtual devices.
-
-- new function `pcms()` to list available PCM devices.
-
-- `mixers()` and `Mixer()` take an additional `device` keyword argument.
-  This allows to list or open virtual devices.
-
-- The default behaviour of `Mixer()` without any arguments has changed.
-  Now Mixer() will try to open the `default` Mixer instead of the Mixer
-  that is associated with card 0.
-
-- fix a memory leak under Python 3.x
-
-- some more memory leaks in error conditions fixed.
-
-# Version 0.7:
-- fixed several memory leaks (patch 3372909), contributed by Erik Kulyk)
-
-# Version 0.6:
-- mostly reverted patch 2594366: alsapcm_setup did not do complete error
-checking for good reasons; some ALSA functions in alsapcm_setup may fail without
-rendering the device unusable
-
-# Version 0.5:
-- applied patch 2777035: Fixed setrec method in alsaaudio.c
-  This included a mixertest with more features
-- fixed/applied patch 2594366: alsapcm_setup does not do any error checking
-
-# Version 0.4:
-- API changes: mixers() and Mixer() now take a card index instead of a
-  card name as optional parameter.
-- Support for Python 3.0
-- Documentation converted to reStructuredText; use Sphinx instead of LaTeX.
-- added `cards()`
-- added `PCM.close()`
-- added `Mixer.close()`
-- added `mixer.getenum()`
-
-# Version 0.3:
-- wrapped blocking calls with `Py_BEGIN_ALLOW_THREADS`/`Py_END_ALLOW_THREADS`
-- added pause
-
-# Version 0.2:
-- Many bugfixes related to playback in particular
-- Module documentation in the doc subdirectory
-
-# Version 0.1:
-- Initial version

NOTES.md

@@ -0,0 +1,11 @@
+# Publishing the documentation
+
+ - Install Sphinx; `sudo pip install sphinx`
+ - Clone gh-pages branch: `cd doc; git clone -b gh-pages git@github.com:larsimmisch/pyalsaaudio.git gh-pages`
+ - `cd doc; make publish`
+
+# Release procedure
+
+ - Update version number in setup.py
+ - Create tag and push it, i.e. `git tag x.y.z; git push origin x.y.z`
+ - `python setup.py sdist upload -r pypi` 

doc/README.md

@@ -1,26 +1,3 @@
-# Make a new release
-
-Update the version in setup.py
-
-    pyalsa_version = '0.9.0'
-
-Commit and push the update.
-
-Create and push a tag naming the version (i.e. 0.9.0):
-
-    git tag 0.9.0
-    git push origin 0.9.0
-
-Create the package:
-
-    python3 setup.py sdist
-
-Upload the package
-
-    twine upload dist/*
-
-Don't forget to update the documentation.
-
 # Publish the documentation
 
 The documentation is published through the `gh-pages` branch.

doc/index.rst

@@ -1,3 +1,8 @@
+.. alsaaudio documentation documentation master file, created by
+   sphinx-quickstart on Thu Mar 30 23:52:21 2017.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
 alsaaudio documentation
 ===================================================
 
@@ -13,13 +18,15 @@ Download
 ========
 
 * `Download from pypi <https://pypi.python.org/pypi/pyalsaaudio>`_
-
+  
+      
 Github
 ======
 
 * `Repository <https://github.com/larsimmisch/pyalsaaudio/>`_
 * `Bug tracker <https://github.com/larsimmisch/pyalsaaudio/issues>`_
 
+ 
 Indices and tables
 ==================
 
@@ -27,3 +34,5 @@ Indices and tables
 * :ref:`modindex`
 * :ref:`search`
 
+    
+  

doc/libalsaaudio.rst

@@ -5,18 +5,41 @@
 .. module:: alsaaudio
    :platform: Linux
 
+
+.. % \declaremodule{builtin}{alsaaudio}	% standard library, in C
+.. % not standard, in C
+
 .. moduleauthor:: Casper Wilstrup <cwi@aves.dk>
 .. moduleauthor:: Lars Immisch <lars@ibp.de>
+                  
+.. % Author of the module code;
+
+
 
 The :mod:`alsaaudio` module defines functions and classes for using ALSA.
 
-.. function:: pcms(pcmtype=PCM_PLAYBACK)
+.. % ---- 3.1. ----
+.. % For each function, use a ``funcdesc'' block.  This has exactly two
+.. % parameters (each parameters is contained in a set of curly braces):
+.. % the first parameter is the function name (this automatically
+.. % generates an index entry); the second parameter is the function's
+.. % argument list.  If there are no arguments, use an empty pair of
+.. % curly braces.  If there is more than one argument, separate the
+.. % arguments with backslash-comma.  Optional parts of the parameter
+.. % list are contained in \optional{...} (this generates a set of square
+.. % brackets around its parameter).  Arguments are automatically set in
+.. % italics in the parameter list.  Each argument should be mentioned at
+.. % least once in the description; each usage (even inside \code{...})
+.. % should be enclosed in \var{...}.
+
+
+.. function:: pcms([type=PCM_PLAYBACK])
 
    List available PCM devices by name.
-
+   
    Arguments are:
 
-   * *pcmtype* - can be either :const:`PCM_CAPTURE` or :const:`PCM_PLAYBACK`
+   * *type* - can be either :const:`PCM_CAPTURE` or :const:`PCM_PLAYBACK`
      (default).  
 
    **Note:**
@@ -39,12 +62,7 @@ The :mod:`alsaaudio` module defines functions and classes for using ALSA.
    List the available ALSA cards by name. This function is only moderately
    useful. If you want to see a list of available PCM devices, use :func:`pcms`
    instead.
-
-..
-   Omitted by intention due to being superseded by cards():
-
-   .. function:: card_indexes()
-   .. function:: card_name()
+   
 
 .. function:: mixers(cardindex=-1, device='default')
 
@@ -55,14 +73,12 @@ The :mod:`alsaaudio` module defines functions and classes for using ALSA.
      the `device` keyword argument is ignored. ``0`` is the first hardware sound
      card.
 
-     **Note:** This should not be used, as it bypasses most of ALSA's configuration.
-
    * *device* - the name of the device on which the mixer resides. The default
      is ``'default'``.
 
    **Note:** For a list of available controls, you can also use ``amixer`` on
    the commandline::
-
+      
       $ amixer
 
    To elaborate the example, calling :func:`mixers` with the argument
@@ -76,16 +92,12 @@ The :mod:`alsaaudio` module defines functions and classes for using ALSA.
       $ amixer -D foo
 
    *Changed in 0.8*:
-
+   
    - The keyword argument `device` is new and can be used to
      select virtual devices. As a result, the default behaviour has subtly
      changed. Since 0.8, this functions returns the mixers for the default
      device, not the mixers for the first card.
 
-.. function:: asoundlib_version()
-
-   Return a Python string containing the ALSA version found.
-
 
 .. _pcm-objects:
 
@@ -96,7 +108,7 @@ PCM objects in :mod:`alsaaudio` can play or capture (record) PCM
 sound through speakers or a microphone. The PCM constructor takes the
 following arguments:
 
-.. class:: PCM(type=PCM_PLAYBACK, mode=PCM_NORMAL, rate=44100, channels=2, format=PCM_FORMAT_S16_LE, periodsize=32, periods=4, device='default', cardindex=-1)
+.. class:: PCM(type=PCM_PLAYBACK, mode=PCM_NORMAL, device='default', cardindex=-1)
 
    This class is used to represent a PCM device (either for playback and
    recording). The arguments are:
@@ -105,16 +117,78 @@ following arguments:
      (default).  
    * *mode* - can be either :const:`PCM_NONBLOCK`, or :const:`PCM_NORMAL`
      (default). 
-   * *rate* - the sampling rate in Hz. Typical values are ``8000`` (mainly used for telephony), ``16000``, ``44100`` (default), ``48000`` and ``96000``.
-   * *channels* - the number of channels. The default value is 2 (stereo).
-   * *format* - the data format. This controls how the PCM device interprets data for playback, and how data is encoded in captures. 
-     The default value is :const:`PCM_FORMAT_S16_LE`.
+   * *device* - the name of the PCM device that should be used (for example
+     a value from the output of :func:`pcms`). The default value is
+     ``'default'``.
+   * *cardindex* - the card index. If this argument is given, the device name
+     is constructed as 'hw:*cardindex*' and
+     the `device` keyword argument is ignored.
+     ``0`` is the first hardware sound card.
+
+   This will construct a PCM object with these default settings:
+
+   * Sample format: :const:`PCM_FORMAT_S16_LE`
+   * Rate: 44100 Hz 
+   * Channels: 2
+   * Period size: 32 frames
+
+   *Changed in 0.8:*
+   
+   - The `card` keyword argument is still supported,
+     but deprecated. Please use `device` instead.
+
+   - The keyword argument `cardindex` was added.
+
+   The `card` keyword is deprecated because it guesses the real ALSA
+   name of the card. This was always fragile and broke some legitimate usecases.
+   
+     
+PCM objects have the following methods:
+
+
+.. method:: PCM.pcmtype()
+
+   Returns the type of PCM object. Either :const:`PCM_CAPTURE` or
+   :const:`PCM_PLAYBACK`.
+
+
+.. method:: PCM.pcmmode()
+
+   Return the mode of the PCM object. One of :const:`PCM_NONBLOCK`,
+   :const:`PCM_ASYNC`, or :const:`PCM_NORMAL`
+
+
+.. method:: PCM.cardname()
+
+   Return the name of the sound card used by this PCM object.
+
+
+.. method:: PCM.setchannels(nchannels)
+
+   Used to set the number of capture or playback channels. Common
+   values are: ``1`` = mono, ``2`` = stereo, and ``6`` = full 6 channel audio.
+   Few sound cards support more than 2 channels
+
+
+.. method:: PCM.setrate(rate)
+
+   Set the sample rate in Hz for the device. Typical values are ``8000``
+   (mainly used for telephony), ``16000``, ``44100`` (CD quality),
+   ``48000`` and ``96000``.
+
+
+.. method:: PCM.setformat(format)
+
+   The sound *format* of the device. Sound format controls how the PCM device
+   interpret data for playback, and how data is encoded in captures.
+
+   The following formats are provided by ALSA:
 
    =========================  ===============
-        Format                Description
+          Format                Description
    =========================  ===============
    ``PCM_FORMAT_S8``          Signed 8 bit samples for each channel
-   ``PCM_FORMAT_U8``          Unsigned 8 bit samples for each channel
+   ``PCM_FORMAT_U8``          Signed 8 bit samples for each channel
    ``PCM_FORMAT_S16_LE``      Signed 16 bit samples for each channel Little Endian byte order)
    ``PCM_FORMAT_S16_BE``      Signed 16 bit samples for each channel (Big Endian byte order)
    ``PCM_FORMAT_U16_LE``      Unsigned 16 bit samples for each channel (Little Endian byte order)
@@ -141,176 +215,15 @@ following arguments:
    ``PCM_FORMAT_U24_3LE``     Unsigned 24 bit samples for each channel (Little Endian byte order in 3 bytes)
    ``PCM_FORMAT_U24_3BE``     Unsigned 24 bit samples for each channel (Big Endian byte order in 3 bytes)
    =========================  ===============
-
-   * *periodsize* - the period size in frames.
-     Make sure you understand :ref:`the meaning of periods <term-period>`.
-     The default value is 32, which is below the actual minimum of most devices,
-     and will therefore likely be larger in practice.
-   * *periods* - the number of periods in the buffer. The default value is 4.
-   * *device* - the name of the PCM device that should be used (for example
-     a value from the output of :func:`pcms`). The default value is
-     ``'default'``.
-   * *cardindex* - the card index. If this argument is given, the device name
-     is constructed as 'hw:*cardindex*' and
-     the `device` keyword argument is ignored.
-     ``0`` is the first hardware sound card.
-
-     **Note:** This should not be used, as it bypasses most of ALSA's configuration.
-
-   This will construct a PCM object with the given settings.
-
-   *Changed in 0.10:*
-
-   - Added the optional named parameter `periods`.
-
-   *Changed in 0.9:*
-
-   - Added the optional named parameters `rate`, `channels`, `format` and `periodsize`.
-
-   *Changed in 0.8:*
-
-   - The `card` keyword argument is still supported,
-     but deprecated. Please use `device` instead.
-
-   - The keyword argument `cardindex` was added.
-
-   The `card` keyword is deprecated because it guesses the real ALSA
-   name of the card. This was always fragile and broke some legitimate usecases.
-
-PCM objects have the following methods:
-
-.. method:: PCM.info()
-
-   The info function returns a dictionary containing the configuration of a PCM device. As ALSA takes into account limitations of the hardware and software devices the configuration achieved might not correspond to the values used during creation. There is therefore a need to check the realised configuration before processing the sound coming from the device or before sending sound to a device. A small subset of parameters can be set, but cannot be queried. These parameters are stored by alsaaudio and returned as they were given by the user, to distinguish them from parameters retrieved from ALSA these parameters have a name prefixed with **" (call value) "**. Yet another set of properties derives directly from the hardware and can be obtained through ALSA.
    
-   ===========================  =============================  ==================================================================
-        Key                      Description (Reference)            Type       
-   ===========================  =============================  ==================================================================
-   name                         PCM():device                      string
-   card_no                      *index of card*                   integer  (negative indicates device not associable with a card)
-   device_no                    *index of PCM device*             integer 
-   subdevice_no                 *index of PCM subdevice*          integer 
-   state                        *name of PCM state*               string
-   access_type                  *name of PCM access type*         string
-   (call value) type            PCM():type                        integer
-   (call value) type_name       PCM():type                        string
-   (call value) mode            PCM():mode                        integer
-   (call value) mode_name       PCM():mode                        string
-   format                       PCM():format                      integer 
-   format_name                  PCM():format                      string
-   format_description           PCM():format                      string
-   subformat_name               *name of PCM subformat*           string
-   subformat_description        *description of subformat*        string
-   channels                     PCM():channels                    integer
-   rate                         PCM():rate                        integer (Hz)
-   period_time                  *period duration*                 integer (:math:`\mu s`)
-   period_size                  PCM():period_size                 integer (frames)
-   buffer_time                  *buffer time*                     integer (:math:`\mu s`) (negative indicates error)
-   buffer_size                  *buffer size*                     integer (frames) (negative indicates error)
-   get_periods                  *approx. periods in buffer*       integer (negative indicates error)
-   rate_numden                  *numerator, denominator*          tuple (integer (Hz), integer (Hz))
-   significant_bits             *significant bits in sample*      integer (negative indicates error)
-   is_batch                     *hw: double buffering*            boolean (True: hardware supported)
-   is_block_transfer            *hw: block transfer*              boolean (True: hardware supported)
-   is_double                    *hw: double buffering*            boolean (True: hardware supported)
-   is_half_duplex               *hw: half-duplex*                 boolean (True: hardware supported)
-   is_joint_duplex              *hw: joint-duplex*                boolean (True: hardware supported)
-   can_overrange                *hw: overrange detection*         boolean (True: hardware supported)
-   can_mmap_sample_resolution   *hw: sample-resol. mmap*          boolean (True: hardware supported)
-   can_pause                    *hw: pause*                       boolean (True: hardware supported)
-   can_resume                   *hw: resume*                      boolean (True: hardware supported)
-   can_sync_start               *hw: synchronized start*          boolean (True: hardware supported) 
-   ===========================  =============================  ==================================================================
-
-   The italicized descriptions give a summary of the "full" description as it can be found in the  `ALSA documentation <https://www.alsa-project.org/alsa-doc>`_. "hw:": indicates that the property indicated relates to the hardware. Parameters passed to the PCM object during instantation are prefixed with "PCM():", they are described there for the keyword argument indicated after "PCM():".
-
-
-.. method:: PCM.pcmtype()
-
-   Returns the type of PCM object. Either :const:`PCM_CAPTURE` or
-   :const:`PCM_PLAYBACK`.
-
-.. method:: PCM.pcmmode()
-
-   Return the mode of the PCM object. One of :const:`PCM_NONBLOCK`,
-   :const:`PCM_ASYNC`, or :const:`PCM_NORMAL`
-
-.. method:: PCM.cardname()
-
-   Return the name of the sound card used by this PCM object.
-
-..
-   Omitted by intention due to not really fitting the c'tor-based setup concept:
-
-   .. method:: PCM.getchannels()
-
-   Returns list of the device's supported channel counts.
-
-   .. method:: PCM.getratebounds()
-
-   Returns the card's minimum and maximum supported sample rates as
-   a tuple of integers.
-
-   .. method:: PCM.getrates()
-
-   Returns the sample rates supported by the device.
-   The returned value can be of one of the following, depending on
-   the card's properties:
-   * Card supports only a single rate: returns the rate
-   * Card supports a continuous range of rates: returns a tuple of
-     the range's lower and upper bounds (inclusive)
-   * Card supports a collection of well-known rates: returns a list of
-     the supported rates
-
-   .. method:: PCM.getformats()
-
-   Returns a dictionary of supported format codes (integers) keyed by
-   their standard ALSA names (strings).
-
-.. method:: PCM.setchannels(nchannels)
-
-   .. deprecated:: 0.9 Use the `channels` named argument to :func:`PCM`.
-
-.. method:: PCM.setrate(rate)
-
-   .. deprecated:: 0.9 Use the `rate` named argument to :func:`PCM`.
-
-.. method:: PCM.setformat(format)
-
-   .. deprecated:: 0.9 Use the `format` named argument to :func:`PCM`.
 
 .. method:: PCM.setperiodsize(period)
 
-   .. deprecated:: 0.9 Use the `periodsize` named argument to :func:`PCM`.
+   Sets the actual period size in frames. Each write should consist of
+   exactly this number of frames, and each read will return this
+   number of frames (unless the device is in :const:`PCM_NONBLOCK` mode, in
+   which case it may return nothing at all)
 
-.. method:: PCM.info()
-
-   Returns a dictionary with the PCM object's configured parameters.
-
-   Values are retrieved from the ALSA library if they are available;
-   otherwise they represent those stored by pyalsaaudio, and their keys
-   are prefixed with ' (call value) '.
-
-   *New in 0.9.1*
-
-.. method:: PCM.dumpinfo()
-
-   Dumps the PCM object's configured parameters to stdout.
-
-.. method:: PCM.state()
-
-   Returs the current state of the stream, which can be one of
-   :const:`PCM_STATE_OPEN` (this should not actually happen),
-   :const:`PCM_STATE_SETUP` (after :func:`drop` or :func:`drain`),
-   :const:`PCM_STATE_PREPARED` (after construction),
-   :const:`PCM_STATE_RUNNING`,
-   :const:`PCM_STATE_XRUN`,
-   :const:`PCM_STATE_DRAINING`,
-   :const:`PCM_STATE_PAUSED`,
-   :const:`PCM_STATE_SUSPENDED`, and
-   :const:`PCM_STATE_DISCONNECTED`.
-
-   *New in 0.10*
 
 .. method:: PCM.read()
 
@@ -344,94 +257,22 @@ PCM objects have the following methods:
    return value of zero, if the buffer is full. In this case, the data
    should be written at a later time.
 
-   Note that this call completing means only that the samples were buffered
-   in the kernel, and playout will continue afterwards. Make sure that the
-   stream is drained before discarding the PCM handle.
 
 .. method:: PCM.pause([enable=True])
 
    If *enable* is :const:`True`, playback or capture is paused.
    Otherwise, playback/capture is resumed.
 
-.. method:: PCM.drop()
-
-   Stop the stream and drop residual buffered frames.
-
-   *New in 0.9*
-
-.. method:: PCM.drain()
-
-   For :const:`PCM_PLAYBACK` PCM objects, play residual buffered frames
-   and then stop the stream. In :const:`PCM_NORMAL` mode,
-   this function blocks until all pending playback is drained.
-
-   For :const:`PCM_CAPTURE` PCM objects, this function is not very useful.
-
-   *New in 0.10*
-
-.. method:: PCM.close()
-
-   Closes the PCM device.
-
-   For :const:`PCM_PLAYBACK` PCM objects in :const:`PCM_NORMAL` mode,
-   this function blocks until all pending playback is drained.
 
 .. method:: PCM.polldescriptors()
 
-   Returns a list of tuples of *(file descriptor, eventmask)* that can be
-   used to wait for changes on the PCM with *select.poll*.
+   Returns a tuple of *(file descriptor, eventmask)* that can be used to
+   wait for changes on the mixer with *select.poll*.
 
    The *eventmask* value is compatible with `poll.register`__ in the Python 
    :const:`select` module.
 
-.. method:: PCM.set_tstamp_mode([mode=PCM_TSTAMP_ENABLE])
-
-   Set the ALSA timestamp mode on the device. The mode argument can be set to
-   either :const:`PCM_TSTAMP_NONE` or :const:`PCM_TSTAMP_ENABLE`.
-
-.. method:: PCM.get_tstamp_mode()
-
-   Return the integer value corresponding to the ALSA timestamp mode. The
-   return value can be either :const:`PCM_TSTAMP_NONE` or :const:`PCM_TSTAMP_ENABLE`.
-
-.. method:: PCM.set_tstamp_type([type=PCM_TSTAMP_TYPE_GETTIMEOFDAY])
-
-   Set the ALSA timestamp mode on the device. The type argument
-   can be set to either :const:`PCM_TSTAMP_TYPE_GETTIMEOFDAY`,
-   :const:`PCM_TSTAMP_TYPE_MONOTONIC` or :const:`PCM_TSTAMP_TYPE_MONOTONIC_RAW`.
-
-.. method:: PCM.get_tstamp_type()
-
-   Return the integer value corresponding to the ALSA timestamp type. The
-   return value can be either :const:`PCM_TSTAMP_TYPE_GETTIMEOFDAY`,
-   :const:`PCM_TSTAMP_TYPE_MONOTONIC` or :const:`PCM_TSTAMP_TYPE_MONOTONIC_RAW`.
-
-.. method:: PCM.htimestamp()
-
-   Return a Python tuple *(seconds, nanoseconds, frames_available_in_buffer)*.
-
-   The type of output is controlled by the tstamp_type, as described in the table below.
-
-   =================================  ===========================================
-            Timestamp Type                             Description
-   =================================  ===========================================
-   ``PCM_TSTAMP_TYPE_GETTIMEOFDAY``   System-wide realtime clock with seconds
-                                      since epoch.
-   ``PCM_TSTAMP_TYPE_MONOTONIC``      Monotonic time from an unspecified starting
-                                      time. Progress is NTP synchronized.
-   ``PCM_TSTAMP_TYPE_MONOTONIC_RAW``  Monotonic time from an unspecified starting
-                                      time using only the system clock.
-   =================================  ===========================================
-
-   The timestamp mode is controlled by the tstamp_mode, as described in the table below.
-
-   =================================  ===========================================
-            Timestamp Mode                             Description
-   =================================  ===========================================
-   ``PCM_TSTAMP_NONE``                No timestamp.
-   ``PCM_TSTAMP_ENABLE``              Update timestamp at every hardware position
-                                      update.
-   =================================  ===========================================
+__ poll_objects_
 
 **A few hints on using PCM devices for playback**
 
@@ -468,10 +309,11 @@ Mixer Objects
 
 Mixer objects provides access to the ALSA mixer API.
 
+
 .. class:: Mixer(control='Master', id=0, cardindex=-1, device='default')
 
    Arguments are:
-
+   
    * *control* - specifies which control to manipulate using this mixer
      object. The list of available controls can be found with the 
      :mod:`alsaaudio`.\ :func:`mixers` function.  The default value is
@@ -487,27 +329,30 @@ Mixer objects provides access to the ALSA mixer API.
 
    * *device* - the name of the device on which the mixer resides. The default
      value is ``'default'``.
-
+   
    *Changed in 0.8*:
-
+   
    - The keyword argument `device` is new and can be used to select virtual
      devices.
-
+  
 Mixer objects have the following methods:
 
 .. method:: Mixer.cardname()
 
    Return the name of the sound card used by this Mixer object
 
+
 .. method:: Mixer.mixer()
 
    Return the name of the specific mixer controlled by this object, For example
    ``'Master'`` or ``'PCM'``
 
+
 .. method:: Mixer.mixerid()
 
    Return the ID of the ALSA mixer controlled by this object.
 
+
 .. method:: Mixer.switchcap()
 
    Returns a list of the switches which are defined by this specific mixer.
@@ -528,6 +373,7 @@ Mixer objects have the following methods:
    To manipulate these switches use the :meth:`setrec` or
    :meth:`setmute` methods
 
+
 .. method:: Mixer.volumecap()
 
    Returns a list of the volume control capabilities of this
@@ -543,7 +389,7 @@ Mixer objects have the following methods:
    'Capture Volume'          Manipulate sound capture volume
    'Joined Capture Volume'   Manipulate sound capture volume for all channels at a time
    ========================  ================
-
+   
 .. method:: Mixer.getenum()
 
    For enumerated controls, return the currently selected item and  the list of
@@ -570,63 +416,58 @@ Mixer objects have the following methods:
    This method will return an empty tuple if the mixer is not an  enumerated
    control.
 
-.. method:: Mixer.setenum(index)
 
-   For enumerated controls, sets the currently selected item.
-   *index* is an index into the list of available enumerated items returned
-   by :func:`getenum`.
+.. method:: Mixer.getmute()
 
-.. method:: Mixer.getrange(pcmtype=PCM_PLAYBACK, units=VOLUME_UNITS_RAW)
+   Return a list indicating the current mute setting for each
+   channel. 0 means not muted, 1 means muted.
+
+   This method will fail if the mixer has no playback switch capabilities.
+
+
+.. method:: Mixer.getrange([direction])
 
    Return the volume range of the ALSA mixer controlled by this object.
-   The value is a tuple of integers whose meaning is determined by the
-   *units* argument.
 
-   The optional *pcmtype* argument can be either :const:`PCM_PLAYBACK` or
+   The optional *direction* argument can be either :const:`PCM_PLAYBACK` or
    :const:`PCM_CAPTURE`, which is relevant if the mixer can control both
    playback and capture volume.  The default value is :const:`PCM_PLAYBACK`
    if the mixer has playback channels, otherwise it is :const:`PCM_CAPTURE`.
 
-   The optional *units* argument can be one of :const:`VOLUME_UNITS_PERCENTAGE`,
-   :const:`VOLUME_UNITS_RAW`, or :const:`VOLUME_UNITS_DB`.
 
-.. method:: Mixer.getvolume(pcmtype=PCM_PLAYBACK, units=VOLUME_UNITS_PERCENTAGE)
+.. method:: Mixer.getrec()
+
+   Return a list indicating the current record mute setting for each channel. 0
+   means not recording, 1 means recording.
+
+   This method will fail if the mixer has no capture switch capabilities.
+
+
+.. method:: Mixer.getvolume([direction])
 
    Returns a list with the current volume settings for each channel. The list
-   elements are integers whose meaning is determined by the *units* argument.
+   elements are integer percentages.
 
-   The optional *pcmtype* argument can be either :const:`PCM_PLAYBACK` or
+   The optional *direction* argument can be either :const:`PCM_PLAYBACK` or
    :const:`PCM_CAPTURE`, which is relevant if the mixer can control both
    playback and capture volume. The default value is :const:`PCM_PLAYBACK`
    if the mixer has playback channels, otherwise it is :const:`PCM_CAPTURE`.
 
-   The optional *units* argument can be one of :const:`VOLUME_UNITS_PERCENTAGE`,
-   :const:`VOLUME_UNITS_RAW`, or :const:`VOLUME_UNITS_DB`.
 
-.. method:: Mixer.setvolume(volume, channel=None, pcmtype=PCM_PLAYBACK, units=VOLUME_UNITS_PERCENTAGE)
+.. method:: Mixer.setvolume(volume, [channel], [direction])
 
    Change the current volume settings for this mixer. The *volume* argument
-   is an integer whose meaning is determined by the *units* argument.
+   controls the new volume setting as an integer percentage.
 
    If the optional argument *channel* is present, the volume is set
    only for this channel. This assumes that the mixer can control the
    volume for the channels independently.
 
-   The optional *pcmtype* argument can be either :const:`PCM_PLAYBACK` or
+   The optional *direction* argument can be either :const:`PCM_PLAYBACK` or
    :const:`PCM_CAPTURE`, which is relevant if the mixer can control both
    playback and capture volume. The default value is :const:`PCM_PLAYBACK`
    if the mixer has playback channels, otherwise it is :const:`PCM_CAPTURE`.
 
-   The optional *units* argument can be one of :const:`VOLUME_UNITS_PERCENTAGE`,
-   :const:`VOLUME_UNITS_RAW`, or :const:`VOLUME_UNITS_DB`.
-
-.. method:: Mixer.getmute()
-
-   Return a list indicating the current mute setting for each channel.
-   0 means not muted, 1 means muted.
-
-   This method will fail if the mixer has no playback switch capabilities.
-
 .. method:: Mixer.setmute(mute, [channel])
 
    Sets the mute flag to a new value. The *mute* argument is either 0 for not
@@ -637,12 +478,6 @@ Mixer objects have the following methods:
 
    This method will fail if the mixer has no playback mute capabilities
 
-.. method:: Mixer.getrec()
-
-   Return a list indicating the current record mute setting for each channel.
-   0 means not recording, 1 means recording.
-
-   This method will fail if the mixer has no capture switch capabilities.
 
 .. method:: Mixer.setrec(capture, [channel])
 
@@ -656,22 +491,20 @@ Mixer objects have the following methods:
 
 .. method:: Mixer.polldescriptors()
 
-   Returns a list of tuples of *(file descriptor, eventmask)* that can be
-   used to wait for changes on the mixer with *select.poll*.
+   Returns a tuple of *(file descriptor, eventmask)* that can be used to
+   wait for changes on the mixer with *select.poll*.
 
    The *eventmask* value is compatible with `poll.register`__ in the Python 
    :const:`select` module.
 
+__ poll_objects_
+
 .. method:: Mixer.handleevents()
 
-   Acknowledge events on the :func:`polldescriptors` file descriptors
+   Acknowledge events on the *polldescriptors* file descriptors
    to prevent subsequent polls from returning the same events again.
    Returns the number of events that were acknowledged.
 
-.. method:: Mixer.close()
-
-   Closes the Mixer device.
-
 **A rant on the ALSA Mixer API**
 
 The ALSA mixer API is extremely complicated - and hardly documented at all.
@@ -694,6 +527,8 @@ Unfortunately, I'm not able to create such a HOWTO myself, since I only
 understand half of the API, and that which I do understand has come from a
 painful trial and error process.
 
+.. % ==== 4. ====
+
 
 .. _pcm-example:
 
@@ -735,7 +570,6 @@ To test PCM playback (on your default soundcard), run::
 
 recordtest.py and playbacktest.py
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
 **recordtest.py** and **playbacktest.py** will record and play a raw
 sound file in CD quality.
 
@@ -757,7 +591,7 @@ Without arguments, **mixertest.py** will list all available *controls* on the
 default soundcard.
 
 The output might look like this::
-
+   
   $ ./mixertest.py
   Available mixer controls:
      'Master'
@@ -805,3 +639,9 @@ argument::
   Capabilities: Playback Volume Playback Mute
   Channel 0 volume: 61%
   Channel 1 volume: 61%
+
+.. rubric:: Footnotes
+
+.. [#f1]   ALSA also allows ``PCM_ASYNC``, but this is not supported yet.
+
+.. _poll_objects: http://docs.python.org/library/select.html#poll-objects

doc/pyalsaaudio.rst

@@ -7,19 +7,33 @@ Introduction
 
 .. |release| replace:: version
 
+.. % At minimum, give your name and an email address.  You can include a
+.. % snail-mail address if you like.
+
+.. % This makes the Abstract go on a separate page in the HTML version;
+.. % if a copyright notice is used, it should go immediately after this.
+.. % 
+
+
 .. _front:
 
 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.
 
+.. % Copyright statement should go here, if needed.
+
+.. % The abstract should be a paragraph or two long, and describe the
+.. % scope of the document.
+
+
 .. topic:: Abstract
 
    This package contains wrappers for accessing the ALSA API from Python. It is
    currently fairly complete for PCM devices and Mixer access. MIDI sequencer
    support is low on our priority list, but volunteers are welcome.
 
-   If you find bugs in the wrappers please use the github issue tracker.
+   If you find bugs in the wrappers please use thegithub issue tracker. 
    Please don't send bug reports regarding ALSA specifically. There are several
    bugs in this API, and those should be reported to the ALSA team - not me.
 
@@ -50,8 +64,8 @@ More information about ALSA may be found on the project homepage
 ALSA and Python
 ===============
 
-The older Linux sound API (OSS) -- which is now deprecated -- is well supported
-by the standard Python library, through the ossaudiodev module. No native ALSA
+The older Linux sound API (OSS) which is now deprecated is well supported from
+the standard Python library, through the ossaudiodev module. No native ALSA
 support exists in the standard library.
 
 There are a few other "ALSA for Python" projects available, including at least
@@ -92,7 +106,6 @@ And then as root:  ---   ::
 
    # python setup.py install
 
-
 *******
 Testing
 *******
@@ -117,7 +130,7 @@ with ``Ctl-C``.
 
 Play back the recording with::
 
-   $ python playbacktest.py -d <device> <filename>
+   $ python playbacktest.py-d <device>  <filename>
 
 There is a minimal test suite in :code:`test.py`, but it is
 a bit dependent on the ALSA configuration and may fail without indicating

doc/terminology.rst

@@ -19,7 +19,7 @@ Sample
 
    Musically, the sample size determines the dynamic range. The
    dynamic range is the difference between the quietest and the
-   loudest signal that can be reproduced.
+   loudest signal that can be resproduced.
 
 Frame
    A frame consists of exactly one sample per channel. If there is only one 
@@ -28,9 +28,9 @@ Frame
 
 Frame size
    This is the size in bytes of each frame. This can vary a lot: if each sample
-   is 8 bits, and we're handling mono sound, the frame size is one byte.
-   For six channel audio with 64 bit floating point samples, the frame size
-   is 48 bytes.
+    is 8 bits, and we're handling mono sound, the frame size is one byte. 
+	Similarly in 6 channel audio with 64 bit floating point samples, the frame 
+	size is 48 bytes
 
 Rate
    PCM sound consists of a flow of sound frames. The sound rate controls how 
@@ -38,7 +38,7 @@ Rate
    means that a new frame is played or captured 8000 times per second.
 
 Data rate
-   This is the number of bytes which must be consumed or provided per
+   This is the number of bytes, which must be recorded or provided per
    second at a certain frame size and rate.
 
    8000 Hz mono sound with 8 bit (1 byte) samples has a data rate of
@@ -46,40 +46,24 @@ Data rate
 
    At the other end of the scale, 96000 Hz, 6 channel sound with 64
    bit (8 bytes) samples has a data rate of 96000 \* 6 \* 8 = 4608
-   kb/s (almost 5 MB sound data per second).
-
-   If the data rate requirement is not met, an overrun (on capture) or
-   underrun (on playback) occurs; the term "xrun" is used to refer to
-   either event.
-
-.. _term-period:
+   kb/s (almost 5 MB sound data per second)
 
 Period
-   The CPU processes sample data in chunks of frames, so-called periods
-   (also called fragments by some systems). The operating system kernel's
-   sample buffer must hold at least two periods (at any given time, one
-   is processed by the sound hardware, and one by the CPU).
-
-   The completion of a *period* triggers a CPU interrupt, which causes
-   processing and context switching overhead. Therefore, a smaller period
-   size causes higher CPU resource usage at a given data rate.
-
-   A bigger size of the *buffer* improves the system's resilience to xruns.
-   The buffer being split into a bigger number of smaller periods also does
-   that, as it allows it to be drained / topped up sooner.
-
-   On the other hand, a bigger size of the *buffer* also increases the
-   playback latency, that is, the time it takes for a frame from being
-   sent out by the application to being actually audible.
-
-   Similarly, a bigger *period* size increases the capture latency.
-
-   The trade-off between latency, xrun resilience, and resource usage
-   must be made depending on the application.
+   When the hardware processes data this is done in chunks of frames. The time
+   interval between each processing (A/D or D/A conversion) is known
+   as the period.
+   The size of the period has direct implication on the latency of the
+   sound input or output. For low-latency the period size should be
+   very small, while low CPU resource usage would usually demand
+   larger period sizes. With ALSA, the CPU utilization is not impacted
+   much by the period size, since the kernel layer buffers multiple
+   periods internally, so each period generates an interrupt and a
+   memory copy, but userspace can be slower and read or write multiple
+   periods at the same time.
 
 Period size
-   This is the size of each period in frames. *Not bytes, but frames!*
-   In :mod:`alsaaudio` the period size is set directly, and it is
+   This is the size of each period in Hz. *Not bytes, but Hz!.* In 
+   :mod:`alsaaudio` the period size is set directly, and it is
    therefore important to understand the significance of this
    number. If the period size is configured to for example 32,
    each write should contain exactly 32 frames of sound data, and each

isine.py

@@ -56,7 +56,10 @@ class SinePlayer(Thread):
     def __init__(self, frequency = 440.0):
         Thread.__init__(self)
         self.setDaemon(True)
-        self.device = alsaaudio.PCM(channels=channels, format=format, rate=sampling_rate)
+        self.device = alsaaudio.PCM()
+        self.device.setchannels(channels)
+        self.device.setformat(format)
+        self.device.setrate(sampling_rate)
         self.queue = Queue()
         self.change(frequency)
 

loopback.py

@@ -1,397 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-
-
-import sys
-import select
-import logging
-import re
-import struct
-import subprocess
-from datetime import datetime, timedelta
-from alsaaudio import (PCM, pcms, PCM_PLAYBACK, PCM_CAPTURE, PCM_NONBLOCK, Mixer,
-	PCM_STATE_OPEN, PCM_STATE_SETUP, PCM_STATE_PREPARED, PCM_STATE_RUNNING, PCM_STATE_XRUN, PCM_STATE_DRAINING,
-	PCM_STATE_PAUSED, PCM_STATE_SUSPENDED, ALSAAudioError)
-from argparse import ArgumentParser
-
-poll_names = {
-	select.POLLIN: 'POLLIN',
-	select.POLLPRI: 'POLLPRI',
-	select.POLLOUT: 'POLLOUT',
-	select.POLLERR: 'POLLERR',
-	select.POLLHUP: 'POLLHUP',
-	select.POLLRDHUP: 'POLLRDHUP',
-	select.POLLNVAL: 'POLLNVAL'
-}
-
-state_names = {
-	PCM_STATE_OPEN: 'PCM_STATE_OPEN',
-	PCM_STATE_SETUP: 'PCM_STATE_SETUP',
-	PCM_STATE_PREPARED: 'PCM_STATE_PREPARED',
-	PCM_STATE_RUNNING: 'PCM_STATE_RUNNING',
-	PCM_STATE_XRUN: 'PCM_STATE_XRUN',
-	PCM_STATE_DRAINING: 'PCM_STATE_DRAINING',
-	PCM_STATE_PAUSED: 'PCM_STATE_PAUSED',
-	PCM_STATE_SUSPENDED: 'PCM_STATE_SUSPENDED'
-}
-
-def poll_desc(mask):
-	return '|'.join([poll_names[bit] for bit, name in poll_names.items() if mask & bit])
-
-class PollDescriptor(object):
-	'''File Descriptor, event mask and a name for logging'''
-	def __init__(self, name, fd, mask):
-		self.name = name
-		self.fd = fd
-		self.mask = mask
-
-	def as_tuple(self):
-		return (self.fd, self.mask)
-
-	@classmethod
-	def from_alsa_object(cls, name, alsaobject, mask=None):
-		# TODO maybe refactor: we ignore objects that have more then one polldescriptor
-		fd, alsamask = alsaobject.polldescriptors()[0]
-
-		if mask is None:
-			mask = alsamask
-
-		return cls(name, fd, mask)
-
-class Loopback(object):
-	'''Loopback state and event handling'''
-
-	def __init__(self, capture, playback_args, volume_handler, run_after_stop=None, run_before_start=None):
-		self.playback_args = playback_args
-		self.playback = None
-		self.volume_handler = volume_handler
-		self.capture_started = None
-		self.last_capture_event = None
-
-		self.capture = capture
-		self.capture_pd = PollDescriptor.from_alsa_object('capture', capture)
-
-		self.run_after_stop = run_after_stop.split(' ')
-		self.run_before_start = run_before_start.split(' ')
-		self.run_after_stop_did_run = False
-
-		self.waitBeforeOpen = False
-		self.queue = []
-
-		self.period_size = 0
-		self.silent_periods = 0
-
-	@staticmethod
-	def compute_energy(data):
-		values = struct.unpack(f'{len(data)//2}h', data)
-		e = 0
-		for v in values:
-			e = e + v * v
-
-		return e
-
-	@staticmethod
-	def run_command(cmd):
-		if cmd:
-			rc = subprocess.run(cmd)
-			if rc.returncode:
-				logging.warning(f'run {cmd}, return code {rc.returncode}')
-			else:
-				logging.info(f'run {cmd}, return code {rc.returncode}')
-
-	def register(self, reactor):
-		reactor.register_timeout_handler(self.timeout_handler)
-		reactor.register(self.capture_pd, self)
-
-	def start(self):
-		# start reading data
-		size, data = self.capture.read()
-		if size:
-			self.queue.append(data)
-
-	def timeout_handler(self):
-		if self.playback and self.capture_started:
-			if self.last_capture_event:
-				if datetime.now() - self.last_capture_event > timedelta(seconds=2):
-					logging.info('timeout - closing playback device')
-					self.playback.close()
-					self.playback = None
-					self.capture_started = None
-					if self.volume_handler:
-						self.volume_handler.stop()
-					self.run_command(self.run_after_stop)
-			return
-
-		self.waitBeforeOpen = False
-
-		if not self.run_after_stop_did_run and not self.playback:
-			if self.volume_handler:
-				self.volume_handler.stop()
-			self.run_command(self.run_after_stop)
-			self.run_after_stop_did_run = True
-
-	def pop(self):
-		if len(self.queue):
-			return self.queue.pop()
-		else:
-			return None
-
-	def handle_capture_event(self, eventmask, name):
-		'''called when data is available for reading'''
-		self.last_capture_event = datetime.now()
-		size, data = self.capture.read()
-		if not size:
-			logging.warning(f'capture event but no data')
-			return False
-
-		energy = self.compute_energy(data)
-		logging.debug(f'energy: {energy}')
-
-		# the usecase is a USB capture device where we get perfect silence when it's idle
-		if energy == 0:
-			self.silent_periods = self.silent_periods + 1
-
-			# turn off playback after two seconds of silence
-			# 2 channels * 2 seconds * 2 bytes per sample
-			fps = self.playback_args['rate']  * 8 // (self.playback_args['periodsize'] * self.playback_args['periods'])
-
-			logging.debug(f'{self.silent_periods} of {fps} silent periods: {self.playback}')
-
-			if self.silent_periods > fps and self.playback:
-				logging.info(f'closing playback due to silence')
-				self.playback.close()
-				self.playback = None
-				if self.volume_handler:
-					self.volume_handler.stop()
-				self.run_command(self.run_after_stop)
-				self.run_after_stop_did_run = True
-
-			if not self.playback:
-				return
-		else:
-			self.silent_periods = 0
-
-		if not self.playback:
-			if self.waitBeforeOpen:
-				return False
-			try:
-				if self.volume_handler:
-					self.volume_handler.start()
-				self.run_command(self.run_before_start)
-				self.playback = PCM(**self.playback_args)
-				self.period_size = self.playback.info()['period_size']
-				logging.info(f'opened playback device with period_size {self.period_size}')
-			except ALSAAudioError as e:
-				logging.info('opening PCM playback device failed: %s', e)
-				self.waitBeforeOpen = True
-				return False
-
-			self.capture_started = datetime.now()
-			logging.info(f'{self.playback} capture started: {self.capture_started}')
-
-		self.queue.append(data)
-
-		if len(self.queue) <= 2:
-			logging.info(f'buffering: {len(self.queue)}')
-			return False
-
-		try:
-			data = self.pop()
-			if data:
-				space = self.playback.avail()
-				written = self.playback.write(data)
-				logging.debug(f'wrote {written} bytes while space was {space}')
-		except ALSAAudioError:
-			logging.error('underrun', exc_info=1)
-
-		return True
-
-	def __call__(self, fd, eventmask, name):
-
-		if fd == self.capture_pd.fd:
-			real_mask = self.capture.polldescriptors_revents([self.capture_pd.as_tuple()])
-			if real_mask:
-				return self.handle_capture_event(real_mask, name)
-			else:
-				logging.debug('null capture event')
-				return False
-		else:
-			real_mask = self.playback.polldescriptors_revents([self.playback_pd.as_tuple()])
-			if real_mask:
-				return self.handle_playback_event(real_mask, name)
-			else:
-				logging.debug('null playback event')
-				return False
-
-class VolumeForwarder(object):
-	'''Volume control event handling'''
-
-	def __init__(self, capture_control, playback_control):
-		self.playback_control = playback_control
-		self.capture_control = capture_control
-		self.active = True
-
-	def start(self):
-		self.active = True
-		if self.volume:
-			self.volume = playback_control.setvolume(self.volume)
-
-	def stop(self):
-		self.active = False
-		self.volume = self.playback_control.getvolume(pcmtype=PCM_CAPTURE)[0]
-
-	def __call__(self, fd, eventmask, name):
-		if not self.active:
-			return
-
-		volume = self.capture_control.getvolume(pcmtype=PCM_CAPTURE)
-		# indicate that we've handled the event
-		self.capture_control.handleevents()
-		logging.info(f'{name} adjusting volume to {volume}')
-		if volume:
-			self.playback_control.setvolume(volume[0])
-
-
-class Reactor(object):
-	'''A wrapper around select.poll'''
-
-	def __init__(self):
-		self.poll = select.poll()
-		self.descriptors = {}
-		self.timeout_handlers = set()
-
-	def register(self, polldescriptor, callable):
-		logging.debug(f'registered {polldescriptor.name}: {poll_desc(polldescriptor.mask)}')
-		self.descriptors[polldescriptor.fd] = (polldescriptor, callable)
-		self.poll.register(polldescriptor.fd, polldescriptor.mask)
-
-	def unregister(self, polldescriptor):
-		self.poll.unregister(polldescriptor.fd)
-		del self.descriptors[polldescriptor.fd]
-
-	def register_timeout_handler(self, callable):
-		self.timeout_handlers.add(callable)
-
-	def unregister_timeout_handler(self, callable):
-		self.timeout_handlers.remove(callable)
-
-	def run(self):
-		last_timeout_ev = datetime.now()
-		while True:
-			# poll for a bit, then send a timeout to registered handlers
-			events = self.poll.poll(0.25)
-			for fd, ev in events:
-				polldescriptor, handler = self.descriptors[fd]
-
-				# very chatty - log all events
-				# logging.debug(f'{polldescriptor.name}: {poll_desc(ev)} ({ev})')
-
-				handler(fd, ev, polldescriptor.name)
-
-			if datetime.now() - last_timeout_ev > timedelta(seconds=0.25):
-				for t in self.timeout_handlers:
-					t()
-				last_timeout_ev = datetime.now()
-
-
-if __name__ == '__main__':
-
-	logging.basicConfig(format='%(asctime)s %(levelname)s %(message)s', level=logging.INFO)
-
-	parser = ArgumentParser(description='ALSA loopback (with volume forwarding)')
-
-	playback_pcms = pcms(pcmtype=PCM_PLAYBACK)
-	capture_pcms = pcms(pcmtype=PCM_CAPTURE)
-
-	if not playback_pcms:
-		logging.error('no playback PCM found')
-		sys.exit(2)
-
-	if not capture_pcms:
-		logging.error('no capture PCM found')
-		sys.exit(2)
-
-	parser.add_argument('-d', '--debug', action='store_true')
-	parser.add_argument('-i', '--input', default=capture_pcms[0])
-	parser.add_argument('-o', '--output', default=playback_pcms[0])
-	parser.add_argument('-r', '--rate', type=int, default=44100)
-	parser.add_argument('-c', '--channels', type=int, default=2)
-	parser.add_argument('-p', '--periodsize', type=int, default=444) # must be divisible by 6 for 44k1
-	parser.add_argument('-P', '--periods', type=int, default=2)
-	parser.add_argument('-I', '--input-mixer', help='Control of the input mixer, can contain the card index, e.g. Digital:2')
-	parser.add_argument('-O', '--output-mixer', help='Control of the output mixer, can contain the card index, e.g. PCM:1')
-	parser.add_argument('-A', '--run-after-stop', help='command to run when the capture device is idle/silent')
-	parser.add_argument('-B', '--run-before-start', help='command to run when the capture device becomes active')
-	parser.add_argument('-V', '--volume', help='Initial volume (default is leave unchanged)')
-
-	args = parser.parse_args()
-
-	if args.debug:
-		logging.getLogger().setLevel(logging.DEBUG)
-
-	playback_args = {
-		'type': PCM_PLAYBACK,
-		'mode': PCM_NONBLOCK,
-		'device': args.output,
-		'rate': args.rate,
-		'channels': args.channels,
-		'periodsize': args.periodsize,
-		'periods': args.periods
-	}
-
-	reactor = Reactor()
-
-	# If args.input_mixer and args.output_mixer are set, forward the capture volume to the playback volume.
-	# The usecase is a capture device that is implemented using g_audio, i.e. the Linux USB gadget driver.
-	# When a USB device (eg. an iPad) is connected to this machine, its volume events will go to the volume control
-	# of the output device
-
-	capture = None
-	playback = None
-	volume_handler = None
-	if args.input_mixer and args.output_mixer:
-		re_mixer = re.compile(r'([a-zA-Z0-9]+):?([0-9+])?')
-
-		input_mixer_card = None
-		m = re_mixer.match(args.input_mixer)
-		if m:
-			input_mixer = m.group(1)
-			if m.group(2):
-				input_mixer_card = int(m.group(2))
-		else:
-			parser.print_usage()
-			sys.exit(1)
-
-		output_mixer_card = None
-		m = re_mixer.match(args.output_mixer)
-		if m:
-			output_mixer = m.group(1)
-			if m.group(2):
-				output_mixer_card = int(m.group(2))
-		else:
-			parser.print_usage()
-			sys.exit(1)
-
-		if input_mixer_card is None:
-			capture = PCM(type=PCM_CAPTURE, mode=PCM_NONBLOCK, device=args.input, rate=args.rate,
-				channels=args.channels, periodsize=args.periodsize, periods=args.periods)
-			input_mixer_card = capture.info()['card_no']
-
-		if output_mixer_card is None:
-			playback = PCM(**playback_args)
-			output_mixer_card = playback.info()['card_no']
-			playback.close()
-
-		playback_control = Mixer(control=output_mixer, cardindex=int(output_mixer_card))
-		capture_control = Mixer(control=input_mixer, cardindex=int(input_mixer_card))
-
-		volume_handler = VolumeForwarder(capture_control, playback_control)
-		reactor.register(PollDescriptor.from_alsa_object('capture_control', capture_control, select.POLLIN), volume_handler)
-
-	if args.volume and playback_control:
-		playback_control.setvolume(int(args.volume))
-
-	loopback = Loopback(capture, playback_args, volume_handler, args.run_after_stop, args.run_before_start)
-	loopback.register(reactor)
-	loopback.start()
-
-	reactor.run()

mixertest.py

@@ -43,42 +43,12 @@ def show_mixer(name, kwargs):
         sys.exit(1)
 
     print("Mixer name: '%s'" % mixer.mixer())
-    volcap = mixer.volumecap()
-    print("Capabilities: %s %s" % (' '.join(volcap),
+    print("Capabilities: %s %s" % (' '.join(mixer.volumecap()),
                                    ' '.join(mixer.switchcap())))
-
-    if "Volume" in volcap or "Joined Volume" in volcap or "Playback Volume" in volcap:
-        pmin, pmax = mixer.getrange(alsaaudio.PCM_PLAYBACK)
-        pmin_keyword, pmax_keyword = mixer.getrange(pcmtype=alsaaudio.PCM_PLAYBACK, units=alsaaudio.VOLUME_UNITS_RAW)
-        pmin_default, pmax_default = mixer.getrange()
-        assert pmin == pmin_keyword
-        assert pmax == pmax_keyword
-        assert pmin == pmin_default
-        assert pmax == pmax_default
-        print("Raw playback volume range {}-{}".format(pmin, pmax))
-        pmin_dB, pmax_dB = mixer.getrange(units=alsaaudio.VOLUME_UNITS_DB)
-        print("dB playback volume range {}-{}".format(pmin_dB / 100.0, pmax_dB / 100.0))
-
-    if "Capture Volume" in volcap or "Joined Capture Volume" in volcap:
-        # Check that `getrange` works with keyword and positional arguments
-        cmin, cmax = mixer.getrange(alsaaudio.PCM_CAPTURE)
-        cmin_keyword, cmax_keyword = mixer.getrange(pcmtype=alsaaudio.PCM_CAPTURE, units=alsaaudio.VOLUME_UNITS_RAW)
-        assert cmin == cmin_keyword
-        assert cmax == cmax_keyword
-        print("Raw capture volume range {}-{}".format(cmin, cmax))
-        cmin_dB, cmax_dB = mixer.getrange(pcmtype=alsaaudio.PCM_CAPTURE, units=alsaaudio.VOLUME_UNITS_DB)
-        print("dB capture volume range {}-{}".format(cmin_dB / 100.0, cmax_dB / 100.0))
-
     volumes = mixer.getvolume()
-    volumes_dB = mixer.getvolume(units=alsaaudio.VOLUME_UNITS_DB)
     for i in range(len(volumes)):
-        print("Channel %i playback volume: %i%% (%.1f dB)" % (i, volumes[i], volumes_dB[i] / 100.0))
-
-    volumes = mixer.getvolume(pcmtype=alsaaudio.PCM_CAPTURE)
-    volumes_dB = mixer.getvolume(pcmtype=alsaaudio.PCM_CAPTURE, units=alsaaudio.VOLUME_UNITS_DB)
-    for i in range(len(volumes)):
-        print("Channel %i capture volume: %i%% (%.1f dB)" % (i, volumes[i], volumes_dB[i] / 100.0))
-
+        print("Channel %i volume: %i%%" % (i,volumes[i]))
+        
     try:
         mutes = mixer.getmute()
         for i in range(len(mutes)):
@@ -118,7 +88,7 @@ def set_mixer(name, args, kwargs):
             mixer.setmute(1, channel)
         else:
             mixer.setmute(0, channel)
-
+        
     elif args in ['rec','unrec']:
         # Enable/disable recording
         if args == 'rec':

playbacktest.py

@@ -1,5 +1,4 @@
-#!/usr/bin/env python3
-# -*- mode: python; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-
+#!/usr/bin/env python
 
 ## playbacktest.py
 ##
@@ -39,15 +38,22 @@ if __name__ == '__main__':
 
     f = open(args[0], 'rb')
 
-    # Open the device in playback mode in Mono, 44100 Hz, 16 bit little endian frames
+    # Open the device in playback mode. 
+    out = alsaaudio.PCM(alsaaudio.PCM_PLAYBACK, device=device)
+
+    # Set attributes: Mono, 44100 Hz, 16 bit little endian frames
+    out.setchannels(1)
+    out.setrate(44100)
+    out.setformat(alsaaudio.PCM_FORMAT_S16_LE)
+
     # The period size controls the internal number of frames per period.
     # The significance of this parameter is documented in the ALSA api.
+    out.setperiodsize(160)
 
-    out = alsaaudio.PCM(alsaaudio.PCM_PLAYBACK, channels=1, rate=44100, format=alsaaudio.PCM_FORMAT_S16_LE, periodsize=160, device=device)
     # Read data from stdin
     data = f.read(320)
     while data:
         out.write(data)
         data = f.read(320)
-    out.close()
+            
         

playwav.py

@@ -1,5 +1,4 @@
-#!/usr/bin/env python3
-# -*- mode: python; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-
+#!/usr/bin/env python
 
 # Simple test script that plays (some) wav files
 
@@ -10,54 +9,57 @@ import wave
 import getopt
 import alsaaudio
 
-def play(device, f):	
+def play(device, f):    
 
-	format = None
+    print('%d channels, %d sampling rate\n' % (f.getnchannels(),
+                                               f.getframerate()))
+    # Set attributes
+    device.setchannels(f.getnchannels())
+    device.setrate(f.getframerate())
 
-	# 8bit is unsigned in wav files
-	if f.getsampwidth() == 1:
-		format = alsaaudio.PCM_FORMAT_U8
-	# Otherwise we assume signed data, little endian
-	elif f.getsampwidth() == 2:
-		format = alsaaudio.PCM_FORMAT_S16_LE
-	elif f.getsampwidth() == 3:
-		format = alsaaudio.PCM_FORMAT_S24_3LE
-	elif f.getsampwidth() == 4:
-		format = alsaaudio.PCM_FORMAT_S32_LE
-	else:
-		raise ValueError('Unsupported format')
+    # 8bit is unsigned in wav files
+    if f.getsampwidth() == 1:
+        device.setformat(alsaaudio.PCM_FORMAT_U8)
+    # Otherwise we assume signed data, little endian
+    elif f.getsampwidth() == 2:
+        device.setformat(alsaaudio.PCM_FORMAT_S16_LE)
+    elif f.getsampwidth() == 3:
+        device.setformat(alsaaudio.PCM_FORMAT_S24_3LE)
+    elif f.getsampwidth() == 4:
+        device.setformat(alsaaudio.PCM_FORMAT_S32_LE)
+    else:
+        raise ValueError('Unsupported format')
 
-	periodsize = f.getframerate() // 8
+    periodsize = f.getframerate() // 8
 
-	print('%d channels, %d sampling rate, format %d, periodsize %d\n' % (f.getnchannels(),
-																		 f.getframerate(),
-																		 format,
-																		 periodsize))
-
-	device = alsaaudio.PCM(channels=f.getnchannels(), rate=f.getframerate(), format=format, periodsize=periodsize, device=device)
-	
-	data = f.readframes(periodsize)
-	while data:
-		# Read data from stdin
-		device.write(data)
-		data = f.readframes(periodsize)
+    device.setperiodsize(periodsize)
+    
+    data = f.readframes(periodsize)
+    while data:
+        # Read data from stdin
+        device.write(data)
+        data = f.readframes(periodsize)
 
 
 def usage():
-	print('usage: playwav.py [-d <device>] <file>', file=sys.stderr)
-	sys.exit(2)
+    print('usage: playwav.py [-d <device>] <file>', file=sys.stderr)
+    sys.exit(2)
 
 if __name__ == '__main__':
 
-	device = 'default'
+    device = 'default'
 
-	opts, args = getopt.getopt(sys.argv[1:], 'd:')
-	for o, a in opts:
-		if o == '-d':
-			device = a
+    opts, args = getopt.getopt(sys.argv[1:], 'd:')
+    for o, a in opts:
+        if o == '-d':
+            device = a
 
-	if not args:
-		usage()
-		
-	with wave.open(args[0], 'rb') as f:
-		play(device, f)
+    if not args:
+        usage()
+        
+    f = wave.open(args[0], 'rb')
+    device = alsaaudio.PCM(device=device)
+
+    play(device, f)
+
+    f.close()

recordtest.py

@@ -1,5 +1,4 @@
-#!/usr/bin/env python3
-# -*- mode: python; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-
+#!/usr/bin/env python
 
 ## recordtest.py
 ##
@@ -23,42 +22,48 @@ import getopt
 import alsaaudio
 
 def usage():
-	print('usage: recordtest.py [-d <device>] <file>', file=sys.stderr)
-	sys.exit(2)
+    print('usage: recordtest.py [-d <device>] <file>', file=sys.stderr)
+    sys.exit(2)
 
 if __name__ == '__main__':
 
-	device = 'default'
+    device = 'default'
 
-	opts, args = getopt.getopt(sys.argv[1:], 'd:')
-	for o, a in opts:
-		if o == '-d':
-			device = a
+    opts, args = getopt.getopt(sys.argv[1:], 'd:')
+    for o, a in opts:
+        if o == '-d':
+            device = a
 
-	if not args:
-		usage()
+    if not args:
+        usage()
 
-	f = open(args[0], 'wb')
+    f = open(args[0], 'wb')
 
-	# Open the device in nonblocking capture mode in mono, with a sampling rate of 44100 Hz 
-	# and 16 bit little endian samples
-	# The period size controls the internal number of frames per period.
-	# The significance of this parameter is documented in the ALSA api.
-	# For our purposes, it is suficcient to know that reads from the device
-	# will return this many frames. Each frame being 2 bytes long.
-	# This means that the reads below will return either 320 bytes of data
-	# or 0 bytes of data. The latter is possible because we are in nonblocking
-	# mode.
-	inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE, alsaaudio.PCM_NONBLOCK, 
-		channels=1, rate=44100, format=alsaaudio.PCM_FORMAT_S16_LE, 
-		periodsize=160, device=device)
+    # Open the device in nonblocking capture mode. The last argument could
+    # just as well have been zero for blocking mode. Then we could have
+    # left out the sleep call in the bottom of the loop
+    inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE, alsaaudio.PCM_NONBLOCK, device=device)
 
-	loops = 1000000
-	while loops > 0:
-		loops -= 1
-		# Read data from device
-		l, data = inp.read()
+    # Set attributes: Mono, 44100 Hz, 16 bit little endian samples
+    inp.setchannels(1)
+    inp.setrate(44100)
+    inp.setformat(alsaaudio.PCM_FORMAT_S16_LE)
 
-		if l:
-			f.write(data)
-			time.sleep(.001)
+    # The period size controls the internal number of frames per period.
+    # The significance of this parameter is documented in the ALSA api.
+    # For our purposes, it is suficcient to know that reads from the device
+    # will return this many frames. Each frame being 2 bytes long.
+    # This means that the reads below will return either 320 bytes of data
+    # or 0 bytes of data. The latter is possible because we are in nonblocking
+    # mode.
+    inp.setperiodsize(160)
+    
+    loops = 1000000
+    while loops > 0:
+        loops -= 1
+        # Read data from device
+        l, data = inp.read()
+      
+        if l:
+            f.write(data)
+            time.sleep(.001)

setup.py

@@ -8,7 +8,7 @@ from setuptools import setup
 from setuptools.extension import Extension
 from sys import version
 
-pyalsa_version = '0.10.1'
+pyalsa_version = '0.8.6'
 
 if __name__ == '__main__':
     setup(
@@ -29,12 +29,12 @@ if __name__ == '__main__':
             'License :: OSI Approved :: Python Software Foundation License',
             'Operating System :: POSIX :: Linux',
             'Programming Language :: Python :: 2',
-            'Programming Language :: Python :: 3',
+            'Programming Language :: Python :: 3',    
             'Topic :: Multimedia :: Sound/Audio',
             'Topic :: Multimedia :: Sound/Audio :: Mixers',
             'Topic :: Multimedia :: Sound/Audio :: Players',
             'Topic :: Multimedia :: Sound/Audio :: Capture/Recording',
             ],
-        ext_modules=[Extension('alsaaudio',['alsaaudio.c'],
+        ext_modules=[Extension('alsaaudio',['alsaaudio.c'], 
                                libraries=['asound'])]
     )

test.py

@@ -1,5 +1,4 @@
-#!/usr/bin/env python3
-# -*- mode: python; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-
+#!/usr/bin/env python
 
 # These are internal tests. They shouldn't fail, but they don't cover all
 # of the ALSA API. Most importantly PCM.read and PCM.write are missing.
@@ -11,177 +10,127 @@
 import unittest
 import alsaaudio
 import warnings
-from contextlib import closing
 
 # we can't test read and write well - these are tested otherwise
-PCMMethods = [
-	('pcmtype', None),
-	('pcmmode', None),
-	('cardname', None)
-]
-
-PCMDeprecatedMethods = [
-	('setchannels', (2,)),
-	('setrate', (44100,)),
-	('setformat', (alsaaudio.PCM_FORMAT_S8,)),
-	('setperiodsize', (320,))
-]
+PCMMethods = [('pcmtype', None),
+              ('pcmmode', None),
+              ('cardname', None),
+              ('setchannels', (2,)), 
+              ('setrate', (44100,)),
+              ('setformat', (alsaaudio.PCM_FORMAT_S8,)),
+              ('setperiodsize', (320,))]
 
 # A clever test would look at the Mixer capabilities and selectively run the
 # omitted tests, but I am too tired for that.
 
 MixerMethods = [('cardname', None),
-				('mixer', None),
-				('mixerid', None),
-				('switchcap', None),
-				('volumecap', None),
-				('getvolume', None),
-				('getrange', None),
-				('getenum', None),
-#				('getmute', None),
-#				('getrec', None),
-#				('setvolume', (60,)),
-#				('setmute', (0,))
-#				('setrec', (0')),
-				]
+                ('mixer', None),
+                ('mixerid', None),
+                ('switchcap', None),
+                ('volumecap', None),
+                ('getvolume', None),
+                ('getrange', None),
+                ('getenum', None),
+#                ('getmute', None),
+#                ('getrec', None),
+#                ('setvolume', (60,)),
+#                ('setmute', (0,))
+#                ('setrec', (0')),
+                ]
 
 class MixerTest(unittest.TestCase):
-	"""Test Mixer objects"""
+    """Test Mixer objects"""
 
-	def testMixer(self):
-		"""Open the default Mixers and the Mixers on every card"""
+    def testMixer(self):
+        """Open the default Mixers and the Mixers on every card"""
+        
+        for c in alsaaudio.card_indexes():
+            mixers = alsaaudio.mixers(cardindex=c)
+            
+            for m in mixers:
+                mixer = alsaaudio.Mixer(m, cardindex=c)
+                mixer.close()
 
-		for c in alsaaudio.card_indexes():
-			mixers = alsaaudio.mixers(cardindex=c)
+    def testMixerAll(self):
+        "Run common Mixer methods on an open object"
 
-			for m in mixers:
-				mixer = alsaaudio.Mixer(m, cardindex=c)
-				mixer.close()
+        mixers = alsaaudio.mixers()
+        mixer = alsaaudio.Mixer(mixers[0])
 
-	def testMixerAll(self):
-		"Run common Mixer methods on an open object"
+        for m, a in MixerMethods:
+            f = alsaaudio.Mixer.__dict__[m]
+            if a is None:
+                f(mixer)
+            else:
+                f(mixer, *a)
 
-		mixers = alsaaudio.mixers()
-		mixer = alsaaudio.Mixer(mixers[0])
+        mixer.close()
 
-		for m, a in MixerMethods:
-			f = alsaaudio.Mixer.__dict__[m]
-			if a is None:
-				f(mixer)
-			else:
-				f(mixer, *a)
+    def testMixerClose(self):
+        """Run common Mixer methods on a closed object and verify it raises an 
+        error"""
 
-		mixer.close()
+        mixers = alsaaudio.mixers()
+        mixer = alsaaudio.Mixer(mixers[0])
+        mixer.close()
 
-	def testMixerClose(self):
-		"""Run common Mixer methods on a closed object and verify it raises an
-		error"""
-
-		mixers = alsaaudio.mixers()
-		mixer = alsaaudio.Mixer(mixers[0])
-		mixer.close()
-
-		for m, a in MixerMethods:
-			f = alsaaudio.Mixer.__dict__[m]
-			if a is None:
-				self.assertRaises(alsaaudio.ALSAAudioError, f, mixer)
-			else:
-				self.assertRaises(alsaaudio.ALSAAudioError, f, mixer, *a)
+        for m, a in MixerMethods:
+            f = alsaaudio.Mixer.__dict__[m]
+            if a is None:
+                self.assertRaises(alsaaudio.ALSAAudioError, f, mixer)
+            else:
+                self.assertRaises(alsaaudio.ALSAAudioError, f, mixer, *a)
 
 class PCMTest(unittest.TestCase):
-	"""Test PCM objects"""
+    """Test PCM objects"""
 
-	def testPCM(self):
-		"Open a PCM object on every card"
+    def testPCM(self):
+        "Open a PCM object on every card"
 
-		for c in alsaaudio.card_indexes():
-			pcm = alsaaudio.PCM(cardindex=c)
-			pcm.close()
+        for c in alsaaudio.card_indexes():
+            pcm = alsaaudio.PCM(cardindex=c)
+            pcm.close()
 
-	def testPCMAll(self):
-		"Run all PCM methods on an open object"
+    def testPCMAll(self):
+        "Run all PCM methods on an open object"
 
-		pcm = alsaaudio.PCM()
+        pcm = alsaaudio.PCM()
 
-		for m, a in PCMMethods:
-			f = alsaaudio.PCM.__dict__[m]
-			if a is None:
-				f(pcm)
-			else:
-				f(pcm, *a)
+        for m, a in PCMMethods:
+            f = alsaaudio.PCM.__dict__[m]
+            if a is None:
+                f(pcm)
+            else:
+                f(pcm, *a)
 
-		pcm.close()
+        pcm.close()
 
-	def testPCMClose(self):
-		"Run all PCM methods on a closed object and verify it raises an error"
+    def testPCMClose(self):
+        "Run all PCM methods on a closed object and verify it raises an error"
 
-		pcm = alsaaudio.PCM()
-		pcm.close()
+        pcm = alsaaudio.PCM()
+        pcm.close()
 
-		for m, a in PCMMethods:
-			f = alsaaudio.PCM.__dict__[m]
-			if a is None:
-				self.assertRaises(alsaaudio.ALSAAudioError, f, pcm)
-			else:
-				self.assertRaises(alsaaudio.ALSAAudioError, f, pcm, *a)
-
-	def testPCMDeprecated(self):
-		with warnings.catch_warnings(record=True) as w:
-			# Cause all warnings to always be triggered.
-			warnings.simplefilter("always")
-
-			try:
-				pcm = alsaaudio.PCM(card='default')
-			except alsaaudio.ALSAAudioError:
-				pass
-
-			# Verify we got a DepreciationWarning
-			self.assertEqual(len(w), 1, "PCM(card='default') expected a warning" )
-			self.assertTrue(issubclass(w[-1].category, DeprecationWarning), "PCM(card='default') expected a DeprecationWarning")
-
-		for m, a in PCMDeprecatedMethods:
-			with warnings.catch_warnings(record=True) as w:
-				# Cause all warnings to always be triggered.
-				warnings.simplefilter("always")
-
-				pcm = alsaaudio.PCM()
-
-				f = alsaaudio.PCM.__dict__[m]
-				if a is None:
-					f(pcm)
-				else:
-					f(pcm, *a)
-
-				# Verify we got a DepreciationWarning
-				method = "%s%s" % (m, str(a))
-				self.assertEqual(len(w), 1, method + " expected a warning")
-				self.assertTrue(issubclass(w[-1].category, DeprecationWarning), method + " expected a DeprecationWarning")
-
-class PollDescriptorArgsTest(unittest.TestCase):
-	'''Test invalid args for polldescriptors_revents (takes a list of tuples of 2 integers)'''
-	def testArgsNoList(self):
-		with closing(alsaaudio.PCM()) as pcm:
-			with self.assertRaises(TypeError):
-				pcm.polldescriptors_revents('foo')
-
-	def testArgsListButNoTuples(self):
-		with closing(alsaaudio.PCM()) as pcm:
-			with self.assertRaises(TypeError):
-				pcm.polldescriptors_revents(['foo', 1])
-
-	def testArgsListButInvalidTuples(self):
-		with closing(alsaaudio.PCM()) as pcm:
-			with self.assertRaises(TypeError):
-				pcm.polldescriptors_revents([('foo', 'bar')])
-
-	def testArgsListTupleWrongLength(self):
-		with closing(alsaaudio.PCM()) as pcm:
-			with self.assertRaises(TypeError):
-				pcm.polldescriptors_revents([(1, )])
-
-			with self.assertRaises(TypeError):
-				pcm.polldescriptors_revents([(1, 2, 3)])
+        for m, a in PCMMethods:
+            f = alsaaudio.PCM.__dict__[m]
+            if a is None:
+                self.assertRaises(alsaaudio.ALSAAudioError, f, pcm)
+            else:
+                self.assertRaises(alsaaudio.ALSAAudioError, f, pcm, *a)
 
+    def testPCMDeprecated(self):
+        with warnings.catch_warnings(record=True) as w:
+            # Cause all warnings to always be triggered.
+            warnings.simplefilter("always")
 
+            try:
+                pcm = alsaaudio.PCM(card='default')
+            except alsaaudio.ALSAAudioError:
+                pass
+                
+            # Verify we got a DepreciationWarning
+            assert len(w) == 1
+            assert issubclass(w[-1].category, DeprecationWarning)
+                
 if __name__ == '__main__':
-	unittest.main()
+    unittest.main()