PyAlsaCap

PyAlsaCap is a tool inspired from alsacap written by Volker Schatz.

alsacap is a C command line tool allowing user to query soundcards (formats, capabilities), pyalsacap.py is a Python 3 alsacap clone that mimic alsacap. PyAlsaCap can also be used as a Python module, because it does not only print sound card information but alsa generates a Python3 data structure with this informations.

PyAlsaCap query directly libasound2 alsa C-library using Python ctypes module.

State

PyAlsaCap is not complete, all the alsacap args are not handled.

Usage

You can use PyAlsaCap from shell:

luser@computer ~ $ ./pyalsacap.py -R
*** Scanning for recording devices ***
Card 0, ID `Intel', name `HDA Intel'
  Device 0, ID `AD198x Analog', name `AD198x Analog', 2 subdevices (2 available)
    2 channels, sampling rate 8000..192000 Hz
    Sample formats: S16_LE
      Subdevice 0, name `subdevice #0'
      Subdevice 1, name `subdevice #0'
Card 29, ID `ThinkPadEC', name `ThinkPad Console Audio Control'

You can compare with alsacap output:

luser@computer ~ $ ./alsacap -R
*** Scanning for recording devices ***
Card 0, ID `Intel', name `HDA Intel'
  Device 0, ID `AD198x Analog', name `AD198x Analog', 2 subdevices (2 available)
    2 channels, sampling rate 8000..192000 Hz
    Sample formats: S16_LE, S32_LE
      Subdevice 0, name `subdevice #0'
      Subdevice 1, name `subdevice #1'
Card 29, ID `ThinkPadEC', name `ThinkPad Console Audio Control'

You can use PyAlsaCap from Python:

In [1]: from pyalsacap import *
In [2]: insp = Inspector()
In [3]: cards = insp.GetCards()
In [4]: cards
Out[4]:
{
    0: {
        'id': 'Intel',
        'name': 'HDA Intel',
        'devices': {
            0: {
                'channels': [2, 2],
                'formats': ['S16_LE'],
                'id': 'AD198x Analog',
                'name': 'AD198x Analog',
                'rate': [8000, 192000],
                'subdevices_available': 1,
                'subdevices': {
                    0: {
                        'name': 'subdevice #0'
                    }
                }
            },
            1: {
                'channels': [2, 2],
                'formats': ['S16_LE'],
                'id': 'AD198x Digital',
                'name': 'AD198x Digital',
                'rate': [44100, 192000],
                'subdevices_available': 1,
                'subdevices': {
                    0: {
                        'name': 'subdevice #0'
                    }
                }
            }
        }
    },
    29: {
        'id': 'ThinkPadEC',
        'name': 'ThinkPad Console Audio Control',
        'devices': {
        }
    }
}

Author

PyAlsaCap is written by Thomas Debesse pyalsacap@illwieckz.net.

Original alsacap is written by Volker Schatz (alsacap on the volkerschatz.com domain).

License

PyAlsaCap is distributed under the free non-copyleft ISC license.

Useful links:

Volker Schatz's alsacap source code;
PyAlsaCap : Python, pointeurs, et cartes sons…, a french blog entry that present the first public version of pyAlsaCap with some explanation (can be used as a french tutorial for programming in Python with ctypes);
Python official website;
Python ctypes module documentation;
Advanced Linux Sound Architecture (ALSA) project homepage.

illwieckz / pyalsacap