listAudioDevices

List available ALSA audio devices

Syntax

devices = listAudioDevices(raspPiObj,audioType)

Description

devices = listAudioDevices(raspPiObj,audioType) returns a list of Advanced Linux Sound Architecture (ALSA) audio devices connected to your Raspberry Pi™ hardware. The type of listed audio devices (capture or playback) depends on the audioType specified in the function.

Examples

List Available ALSA Audio Input Devices

To list all connected ALSA audio input devices:

1. Create a connection to the Raspberry Pi hardware.

   raspPiObj = raspberrypi('192.168.1.5','pi','raspberrypi')

   rasPiObj = 
   
     raspberrypi with properties:
   
       DeviceAddress: '192.168.1.5'
                Port: 22

   For more information on raspberrypi, see raspberrypi.

2. Use the listAudioDevices function. In the function, specify audioType as 'capture'. The function returns a structured array with field names that correspond to the properties of ALSA audio input devices connected to raspPiObj.

   devices = listAudioDevices(raspPiObj,'capture')

   devices = 
   
     1×2 struct array with fields:
   
       Name
       Device
       Channels
       BitDepth
       SamplingRate
   

   In this example, the function returns a 1-by-2 array, indicating that two audio input devices are connected to raspPiObj.

3. View the properties of the first ALSA audio input device.

   devices(1)

   ans = 
   
     struct with fields:
   
             Name: ' bcm2835 - bcm2835 ALSA↵'
           Device: '0,0'
         Channels: {'CHANNELS: [1 2]'}
         BitDepth: {'8-bit integer'  '16-bit integer'}
     SamplingRate: {'8000 48000'} 
   

List Available ALSA Audio Output Devices

To list all connected ALSA audio output devices:

1. Create a connection to the Raspberry Pi hardware.

   raspPiObj = raspberrypi('192.168.1.5','pi','raspberrypi')

2. Use the listAudioDevices function. In the function, specify audioType as 'playback'. The function returns a structured array with field names that correspond to the properties of ALSA audio output devices connected to raspPiObj.

   devices = listAudioDevices(raspPiObj, 'playback')

   devices = 
   
     1×3 struct array with fields:
   
       Name
       Device
       Channels
       BitDepth
       SamplingRate
   

   In this example, the function returns a 1-by-3 array, indicating that three audio output devices are connected to raspPiObj.

3. View the properties of the second ALSA audio output device.

   devices(2)

   ans = 
   
     struct with fields:
   
             Name: ' bcm2835 - bcm2835 ALSA↵'
           Device: '0,1'
         Channels: {'CHANNELS: 2'}
         BitDepth: {'8-bit integer'  '16-bit integer'}
     SamplingRate: {'44100 48000'} 
   

Input Arguments

raspPiObj — Connection to Raspberry Pi hardware

raspberrypi object

The object that represents the connection to the Raspberry Pi hardware.

Example: raspPiObj

audioType — Type of audio device

'capture' | 'playback'

Specify the type of audio to be listed:

• 'capture' — All ALSA audio input devices connected to Raspberry Pi.

• 'playback' — All ALSA audio output devices connected to Raspberry Pi.

Example: 'playback'

Data Types: char

Output Arguments

devices — List of connected ALSA audio devices

array

The type of listed audio devices depends on the audioType specified in the function. The resulting structured array contains these details:

• Name: The name of the audio device.

• Device: The device number of the audio device.

• Channels: The number of channels supported by the audio device. For example, in List Available ALSA Audio Output Devices, the audio device supports audio from two channels only.

• BitDepth: The data type in which the audio device reads or sends data.

• SamplingRate: The sample rates supported by the audio device.

Data Types: cell