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.

Note

Simulink^® Online™ does not support the listAudioDevices function currently.

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