Error when recording multi-channel audio with loopback

Question

Charlotte Mock 2022-12-15

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1878922-error-when-recording-multi-channel-audio-with-loopback

评论： Jimmy Lapierre 2022-12-16

I am trying to record multi-channel audio where one channel records audio from a microphone and two channels record "internal" sound (i.e., loopback) that is played via MATLAB to headphones. I am working with a digital audio interface (Focusrite Scarlett), ASIO drivers, Windows 10 and MATLAB R2022b.

With the code below I get the following error message:

Error using audioDeviceWriter/setup

The buffer size parameter of the audio input device must match the buffer size parameter of the audio output device.

Error in audioDeviceWriter/setupImpl

I have checked the buffer size parameter using asiosettings and also the settings of the Focusrite and they are set to the same value. I would assume that this applies to both the outputs and inputs of the Focusrite so I cannot explain the error message.

%% define properties of digital audio interface and recording set-up
device = 'Focusrite USB ASIO';
driver = 'ASIO'; 
Fs = 44100; % sampling frequency
%% set up device reader (for recording)
deviceReader = audioDeviceReader('SampleRate',Fs, ...
'Device',device, ...
'BitDepth','24-bit integer', ...
'Driver',driver, ...
'NumChannels',6, ...
'SamplesPerFrame', Fs/4);
setup(deviceReader); 
%% load audio file and set up device writer (for audio output)
fileReader = dsp.AudioFileReader('metronome90bpm.wav');
fileInfo = audioinfo('metronome90bpm.wav');
deviceWriter = audioDeviceWriter('SampleRate',fileInfo.SampleRate, ...
    'Device',device, ...
    'BitDepth','16-bit integer', ...
    'Driver',driver);
setup(deviceWriter, zeros(fileReader.SamplesPerFrame, ...
    fileInfo.NumChannels));

Each section on its own does its job, i.e., setting up the device reader and then recording something OR setting up the device writer and playing the audio.

I have tried the multichannel recording (with microphone + loopback) when playing an audiofile in the background (so not in MATLAB) with windows media player and then starting a recording using the device reader and that works fine.