Cut random 30secs of audio from an audio recording .wav

Hi I would like to know how to: A) Cut a random 10 seconds out of a 10 minute audio file after, i load audio file. B) I would like to repeat this for all files in a linked folder. C) Save the cut sections as a single audio file in .wav format.

Cheers.

Answer 1

[Pawel Jastrzebski]

This code will allow you to import and export all of the audio files in your current folder:

% get file names in the current folder

    fileNames = dir('*.wav');     % structure
    fileNames = {fileNames.name}; % actual names extracted to cell array

    % read and write file in the loop

    for i = 1:numel(fileNames)

        [y, Fs] = audioread(fileNames{i});

        % code that randomly cuts the the sample

        audiowrite(['out_' fileNames{i}],y,Fs);

    end

To get the portion of the file use the:

• read audio doc: description point 2

If you don't know the duration of each of the files these are the steps you need to take:

• Get the total duration of a file

durationInSeconds = size(y,1)/Fs

• Specify the duration of your sound bite i.e 10s

soundDuration = 10;

• Having all this information, you know that your sound bite can start at any point between 0s and durationInSeconds - soundDuration
• Now you need to generate the random soundbite start using:

randomStart = randi([0, durationInSeconds - soundDuration]);

• Once you've got the start, add the sound bite duration to it, convert to new y and write as a new sample