Extracting a segment from sound file

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Odrisso
Odrisso on 31 Oct 2014
Edited: Rick Rosson on 1 Nov 2014
Hi,
I have a wave file of 100 seconds. And I have a excel file where I marked some areas of that file with start and stop times. like first segment: 2.5 to 3.4 seconds, second segment: 4.6 to 5.2 seconds and so on.
Now, I want to do the following things:
1. I first read the wav file, 2. then read the excel file for start and stop times, 3. then cut the segments from the wave file according to the excel file.
I know the 1st and 2nd part. but stuck in the 3rd one. Please let me know, how to do the 3rd part for this.
  3 Comments
Odrisso
Odrisso on 31 Oct 2014
Hi Analyst,
Here is the code: Here tt is the file with two columns which I extracted from excel.
  • [x,fs] = audioread('15.wav');
  • [M,N] = size(x);
  • L = size(tt,1);
  • for k = 1:L
  • a = x(tt(k,1)*fs+1:tt(k,2)*fs);
  • end
By a, I can find the amplitude values for all marked areas.
But, when I want to see separately each individual area, it shows error of dimensional mismatch. I know this error come because the dimension is not same for each marked file. Now, I can't zero pad them because if I do so the average value will be changed.
So, please let me know, how can I extract every segment and store in different variables.
Image Analyst
Image Analyst on 31 Oct 2014
I think this was maybe a reply for Rick. I didn't ask for this. I suggested you attach the two files . You can still do that. Click paperclip, then "Choose file" then "Attach file". You have to do each one at a time, you can't multi-select files.

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Answers (1)

Rick Rosson
Rick Rosson on 31 Oct 2014
Edited: Rick Rosson on 1 Nov 2014
Here are a few pages from the documentation that will help:
And here is a possible solution that should get you started:
[x,Fs] = audioread('myaudiofile.wav');
[M,N] = size(x);
dt = 1/Fs;
t = dt*(0:M-1)';
figure;
plot(t,x);
segments = xlsread('mydatafile.xlsx','C15:D24');
L = size(segments,1);
for k = 1:L
idx = ( segments(k,1) < t ) & ( t < segments(k,2) ) ;
figure;
plot(t(idx),x(idx));
end
  3 Comments
Rick Rosson
Rick Rosson on 31 Oct 2014
I had not finished my answer yet. Please check it now.
Odrisso
Odrisso on 31 Oct 2014
Hi ,
Thanks a lot. But, I don't want to plot them. I just want to save them in a variable. So from your code I develop this:
Here is the code: Here tt is the file with two columns which I extracted from excel.
  • [x,fs] = audioread('15.wav');
  • [M,N] = size(x);
  • L = size(tt,1);
  • for k = 1:L
  • a = x(tt(k,1)*fs+1:tt(k,2)*fs);
  • endBy a, I can find the amplitude values for all marked areas.
But, when I want to see separately each individual area, it shows error of dimensional mismatch. I know this error come because the dimension is not same for each marked file. Now, I can't zero pad them because if I do so the average value will be changed.
So, please let me know, how can I extract every segment and store in different variables.

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