How to read from audio device and write to .wav file?

I was wondering if it is possible to record audio from your speakers/headset and save it to a .wav file? I was able to write a program that records audio from your microphone and saves it but I am a little stuck on how to capture the audio from something like a youtube video and save it. Any ideas? This is the code I have at the moment and it works great but I want to record the audio output instead of recording my audio input (mic).

deviceReader = audioDeviceReader;
setup(deviceReader);

fileWriter = dsp.AudioFileWriter('test.wav', 'FileFormat', 'WAV');

tic
while toc < 10
        aquiredAudio = deviceReader();
        fileWriter(aquiredAudio);
end

release(deviceReader);
release(fileWriter);

Answer 1

[Walter Roberson]

On Windows, you need a special device driver for that, and it is incompatible with directsound . See https://www.mathworks.com/matlabcentral/answers/386734-how-do-i-get-sound-data-from-a-speaker#answer_309137