How do I save adw modified audio to a wav file

How do I savef this modified adw audio to a wav file without having to play it? Audiowrite here doesn't work here to save.

filename = 'speech_dft.mp3';
SpeedFactor = 4/1;

WindowLen      = 1024;
OverlapLength = 896;

% Define audio source
reader = dsp.AudioFileReader(filename, ...
    'SamplesPerFrame',(WindowLen - OverlapLength));

adw = audioDeviceWriter('SampleRate',reader.SampleRate);

% Define time scale modification object
ats = audioTimeScaler('Window',sqrt(hann(WindowLen,'periodic')), ...
    'OverlapLength',OverlapLength, ...
    'SpeedupFactor', SpeedFactor);

while ~isDone(reader) % THIS PLAYS THE MODIFIED RESULTS
    x = reader();
    y = ats(x); % AUDIO TIME SCALER
    adw(y); % AUDIO DEVICE WRITER
end

% THIS SAVES THE MODIFIED RESULTS
audiowrite('output_file.wav', y, 44100, 'BitsPerSample', 16);

% THIS SAVES the object to a file
% save('adw.mat', 'adw');

release(reader);
release(adw);

Answer 1

[Walter Roberson]

Use dsp.AudioFileWriter

Note: in your current code, the y that you audiowrite() would represent only the last buffer-full of data, and not the entire transformed data.

[mark palmer]

Thanks!

Answer 2

[Sameer]

Hi @mark palmer

To save the modified audio to a WAV file without playing it, you can use a buffer to collect the processed audio data and then write it to a file using "audiowrite".

Here's how you can modify your code:

filename = 'speech_dft.mp3';
SpeedFactor = 4/1;
WindowLen = 1024;
OverlapLength = 896;

% Define audio source
reader = dsp.AudioFileReader(filename, ...
    'SamplesPerFrame', (WindowLen - OverlapLength));

% Define time scale modification object
ats = audioTimeScaler('Window', sqrt(hann(WindowLen, 'periodic')), ...
    'OverlapLength', OverlapLength, ...
    'SpeedupFactor', SpeedFactor);

% Initialize a buffer to store the modified audio
buffer = [];

while ~isDone(reader)
    x = reader();
    y = ats(x); % AUDIO TIME SCALER
    buffer = [buffer; y]; % Append the processed audio to the buffer
end

% Save the entire buffer as a WAV file
audiowrite('output_file.wav', buffer, reader.SampleRate, 'BitsPerSample', 16);

release(reader);

Hope this helps!

[Walter Roberson]

This code suffers from the same buffering problem that I discussed recently in https://www.mathworks.com/matlabcentral/answers/2164200-serial-real-time-plotting-and-storaging-streaming-data-from-arduino-slowing-down-badly-over-time#answer_1541420

[mark palmer]

Thanks, it works! Not sure about the buffering problem, but will look into it.