Export Audio with Volume Automation

Question

Hans Buchele 2021-12-5

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1603640-export-audio-with-volume-automation

回答： Mathieu NOE 2021-12-6

Dear Community,

I would like to print a sinewave with volume automation in mathlab. I am already able to print a stereo wave file with a fixed amplitude. Is it possible to set time points with corresponding amplitude values?

fs = 44100;

i=1/fs;

t = 0:i:2;

phi = 0;

A = 1;

f = 220.0000;

x = A*sin((2*pi*f*t) + phi);

f = 220.0000;

y = A*sin((2*pi*f*t) + phi);

stereo_mtx = [x(:), y(:)];

audiowrite('stereo sound 3.wav', stereo_mtx, fs);

Any help is much appreciated! Thanks

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Answer 1

Mathieu NOE 2021-12-6

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1603640-export-audio-with-volume-automation#answer_848800

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hello Hans

this is my suggestion

fs = 44100; 
dt=1/fs; 
t = 0:dt:2;
phi = 0;
A = 1;
f = 220.0000;
x = A*sin((2*pi*f*t) + phi);
f = 220.0000;
y = A*sin((2*pi*f*t) + phi);
% define volume envelopp by time index + amplitude set points
tt = [0 0.5 1.5 2];
yt = [0 1 0.75 0]; % linear fade in / fade out demo
w = interp1(tt,yt,t); % create window of same length as signal 
y = y.*w; % apply window
stereo_mtx = [x(:), y(:)];
audiowrite('stereo sound 3.wav', stereo_mtx, fs);