Report volume like alsamixer. Maybe.

I have no idea how they calculate dB.

CHANGES

@@ -1,32 +1,3 @@
-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)
 

doc/libalsaaudio.rst

@@ -443,31 +443,35 @@ Mixer objects have the following methods:
    This method will fail if the mixer has no capture switch capabilities.
 
 
-.. method:: Mixer.getvolume([direction])
+.. method:: Mixer.getvolume(direction=PCM_PLAYBACK, unit=Percent)
 
    Returns a list with the current volume settings for each channel. The list
-   elements are integer percentages.
+   elements are percentages or dB values, depending on *unit*.
 
-   The optional *direction* argument can be either :const:`PCM_PLAYBACK` or
+   The *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`.
 
 
-.. method:: Mixer.setvolume(volume, [channel], [direction])
+.. method:: Mixer.setvolume(volume, channel=MIXER_CHANNEL_ALL, direction=PCM_PLAYBACK, unit=Percent)
 
    Change the current volume settings for this mixer. The *volume* argument
-   controls the new volume setting as an integer percentage.
+   controls the new volume setting as either a percentage or a dB value. Both
+   integer and floating point values can be given.
 
-   If the optional argument *channel* is present, the volume is set
+   The *channel* argument can be used to restrict the channels for which the volume is
-   only for this channel. This assumes that the mixer can control the
+   set. By default, the volume of all channels is adjusted. This assumes that the mixer
-   volume for the channels independently.
+   can control the volume for the channels independently.
 
-   The optional *direction* argument can be either :const:`PCM_PLAYBACK` or
+   The *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 *unit* argument determines how the volume value is interpreted, as a prcentage
+   or as a dB value.
+   
 .. method:: Mixer.setmute(mute, [channel])
 
    Sets the mute flag to a new value. The *mute* argument is either 0 for not

doc/pyalsaaudio.rst

@@ -75,7 +75,7 @@ development at the time - and neither are very feature complete.
 I wrote PyAlsaAudio to fill this gap. My long term goal is to have the module
 included in the standard Python library, but that looks currently unlikely.
 
-PyAlsaAudio has full support for sound capture, playback of sound, as well as
+PyAlsaAudio hass full support for sound capture, playback of sound, as well as
 the ALSA Mixer API.
 
 MIDI support is not available, and since I don't own any MIDI hardware, it's

mixertest.py

@@ -46,13 +46,17 @@ def show_mixer(name, kwargs):
     print("Capabilities: %s %s" % (' '.join(mixer.volumecap()),
                                    ' '.join(mixer.switchcap())))
     volumes = mixer.getvolume()
-    for i in range(len(volumes)):
+    for i, v in enumerate(volumes):
-        print("Channel %i volume: %i%%" % (i,volumes[i]))
+        print("Channel %i volume: %.02f%%" % (i, v))
-        
+
+    volumes = mixer.getvolume(unit=alsaaudio.dB)
+    for i, v in enumerate(volumes):
+        print("Channel %i volume: %.02fdB" % (i, v))
+
     try:
         mutes = mixer.getmute()
-        for i in range(len(mutes)):
+        for i, m in enumerate(mutes):
-            if mutes[i]:
+            if m:
                 print("Channel %i is muted" % i)
     except alsaaudio.ALSAAudioError:
         # May not support muting
@@ -60,8 +64,8 @@ def show_mixer(name, kwargs):
 
     try:
         recs = mixer.getrec()
-        for i in range(len(recs)):
+        for i, r in enumerate(recs):
-            if recs[i]:
+            if r:
                 print("Channel %i is recording" % i)
     except alsaaudio.ALSAAudioError:
         # May not support recording

playwav.py

@@ -30,7 +30,7 @@ def play(device, f):
     else:
         raise ValueError('Unsupported format')
 
-    periodsize = f.getframerate() // 8
+    periodsize = f.getframerate() / 8
 
     device.setperiodsize(periodsize)
     

setup.py

@@ -8,7 +8,7 @@ from setuptools import setup
 from setuptools.extension import Extension
 from sys import version
 
-pyalsa_version = '0.8.6'
+pyalsa_version = '0.8.4'
 
 if __name__ == '__main__':
     setup(