Audio Device Reader
Record from sound card
Audio Toolbox / Sources
The Audio Device Reader block reads audio samples using your computer's audio device. The Audio Device Reader block specifies the driver, the device and its attributes, and the data type and size output from your Audio Device Reader block.
A — Output signal
scalar | vector | matrix
The output of the Audio Device Reader block is determined by the block’s parameters. If the block output is a matrix, the columns correspond to independent channels.
O — Number of samples overrun
This port outputs the number of samples overrun while acquiring a frame of data (one output matrix).
To enable this port, select the Output number of samples overrun parameter.
Driver — Driver used to access your audio device
DirectSound (default) |
ASIO drivers do not come pre-installed on Windows machines. To use the
ASIOdriver option, install an ASIO driver outside of MATLAB®.
If Driver is set to
ASIO, open the ASIO UI outside of MATLAB to set the sound card buffer size to the value specified by the Samples per frame parameter. See the documentation of your ASIO driver for more information.
WASAPI drivers are supported for exclusive-mode only.
ASIO and WASAPI drivers do not provide sample rate conversion. For ASIO and WASAPI drivers, set Sample rate (Hz) to a sample rate supported by your audio device.
This parameter applies only on Windows machines. Linux machines always use the ALSA driver. Mac machines always use the CoreAudio driver.
Device — Device used to acquire audio samples
default audio device (default)
The device list is populated with devices available on your computer.
Info — View information about your audio input configuration
This button opens a dialog box that lists your selected audio driver, the full name of your audio device, and the maximum input channels for your configuration. For example:
Sample rate (Hz) — Sample rate your device uses to acquire audio data
44100 (default) | integer
The possible range of Sample rate (Hz) depends on your audio hardware.
Number of channels — Number of channels acquired by your audio device
1 (default) | integer
The number of input channels is also the number of channels (matrix columns) output by the Audio Device Reader block.
To specify which input channels your audio device acquires, on the Advanced tab, select the Use default channel mapping parameter.
Samples per frame — Frame size read from audio device
1024 (default) | integer
Samples per frame is also the device buffer size, and the frame size (number of matrix rows) output by the Audio Device Reader block.
Device bit depth — Data type used by device to acquire audio data
integer (default) |
Data type used by device to acquire audio data, specified as a character vector or string.
Use default channel mapping — Toggle channel mapping source
on (default) | off
When you select this parameter, the block uses the default mapping between the sound card’s input channels and the matrix columns output by this block. When you clear this parameter, you specify the mapping in Device input channels.
Device input channels — Specify nondefault channel mapping
[1:MaximumInputChannels] (default) | scalar | vector
Nondefault map of device channels and matrix output by the Audio Device Reader block, specified as a scalar or vector. For example:
If Device input
channels is specified as
Channel 1 maps to the first column of the output matrix.
Channel 2 maps to the second column of the output matrix.
Channel 3 maps to the third column of the output matrix.
If Device input
channels is specified as
Channel 3 maps to the first column of the output matrix.
Channel 1 maps to the second column of the output matrix.
Channel 2 maps to the third column of the output matrix.
To specify a nondefault mapping, clear the Use default mapping between sound card’s input channels and columns of output of this block parameter.
Output number of samples overrun — Specify additional output port for number of samples overrun
off (default) | on
When you select this parameter, an additional output port, O, is added to the block. The O port outputs the number of samples overrun while acquiring a frame of data (one output matrix).
Output data type — Data type output from block
double (default) |
Data type of the output.
If this parameter is specified as
single, the block outputs data
in the range [–1, 1]. For other data types, the
range is [min, max] of the specified data
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
The executable generated from this block relies on prebuilt
dynamic library files (.dll files) included with MATLAB. Use the
to package the code generated from this object and all the
relevant files in a compressed zip file. Using this zip
file, you can relocate, unpack, and rebuild your project in
another development environment where MATLAB is not installed. For more details, see Run Audio I/O Features Outside MATLAB and Simulink.