MATLAB: Create new .wav files around findpeak outputs

acousticsaudioaudioreadaudiowritefindpeaksSignal Processing Toolboxsoundwav. files

Hi everyone,
I would like to create short .wav files containing the audio data of each detected peak (see plot below as example). I would like the data in each .wav file to include the peak and a buffer on either side of roughly 0.02 s (e.g. black boxes around peaks would each be seperate .wav files). I have include my code so far and added a zip file with a short sample of the data to run code below. 
% Read in audio file
[y,Fs] = audioread('test_MATLABAsk.wav');	
info = audioinfo('test_MATLABAsk.wav');
sound(y,Fs) % Play the sound
% plot the data 
% Create a time component using info
t = 0:seconds(1/Fs):seconds(info.Duration); 
t = t(1:end-1);
figure(1)
plot(t,y)
xlabel('Time (s)')
ylabel('Audio Signal')
% Detect peaks from y
[pk_Fs, locs_Fs] = findpeaks(y,Fs, 'MinPeakDistance',0.03, 'MinPeakHeight',0.01); % See plot example below

Best Answer

Here's how I'd do it:
infile = 'C:\somewhere\somefolder\test_100m.wav';  %I'd recommend you use full path instead of relying on the current directory
outfolder = 'C:\somewhere\someotherfolder';
outformat = 'split%03d.wav';  %using sprintf format to insert peak number
halfwidth = seconds(0.02);  %half width of signal to keep around peak
%read file, convert to timetable, find peak locations
[samples, Fs] = audioread(infile);
audiotable = timetable(samples, 'SampleRate', Fs);
[~, peaklocs] = findpeaks(samples, Fs, 'MinPeakDistance', 0.03, 'MinPeakHeight', 0.01);
%iterate over peaks, extract signal and save to file
for peakidx = 1:numel(peaklocs)
    peaktime = audiotable.Time(peakloc(peakidx));
    tokeep = isbetween(audiotable.Time, peaktime - halfwidth, peaktime + halfwidth);
    audiowrite(fullfile(outfolder, sprintf(outformat, peakidx)), audiotable.samples(tokeep), Fs);    
end
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