Trying to convert whole folder into spectrograms

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Hi, I have a local folder of .wav files that Id like to convert to spectrograms (.png) in another local folder. so I can use it to train my CNN model. This is what I have but it's not working. Also gave no errors. Help please!!
folder = uigetdir(pwd,'*insert source folder path name here*');
filelist = dir(fullfile(folder, '*.wav')); %get list of all wav files in the folder
for fileidx = 1:numel(filelist)
[audioIn,fs] = audioread({});
S = melSpectrogram(audioIn,fs);
save('*insert destination folder path name here*','Cough1.png','-png');

Accepted Answer

jibrahim on 12 Apr 2022
Hi Justine, consider using an audioDatastore to do this. then you don't have to write the for loop. for example:
% This audioDatastore will point to all audio files in folder and its
% subfolders
ads = audioDatastore(folder,IncludeSubfolders=true);
% Write my images here
outputLocation = fullfile(tempdir,"mySpectrograms");
% Create PNGs for all audio files.
function myCustomWriter(audioIn,writeInfo,~)
% Get the sample rate of the audio file
fs = writeInfo.ReadInfo.SampleRate;
% Extract Mel spectrogram
S = melSpectrogram(audioIn,fs);
% Form image name
imagename = strrep(writeInfo.SuggestedOutputName,".wav",".png");
% Save image
Justine Hughes
Justine Hughes on 14 Apr 2022
Okay so when I used imagename as a variable it didnt work but when I put the strrep function to replace imagename in saveas, it worked :) thank you very much!

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More Answers (1)

Rik on 12 Apr 2022
You are inserting all files at once, instead of indexing into the filelist array.
If you want want to store an image you need to use imwrite. Look up the documentation to see several examples. I would suggest generating the file name of the png with fullfile, using filelist(n).folder.
Rik on 12 Apr 2022
You're indexing the field, not the struct.
for fileidx = 1:numel(filelist)
[audioIn,fs] = audioread(filelist(fileidx).name);
S = melSpectrogram(audioIn,fs);
filename = sprintf('Cough%d.png',fileidx);
imagename = fullfile(savefolder,sprintf('Cough_%d.png',fileidx));
imwrite(S,imagename); %save image as png

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