MATLAB: Make .wav signals same size

equallylength

Hello everyone!

I have this problem. I need to read for example 60 wav signals, find the shortest one and cut all of them to the size of shortest.

Process of cut is like this: from the middle of the signal need to cut signal right and left equally to the size of shortest signal.

I upload picture as extra explanation.

Best Answer

See the FAQ: How_can_I_process_a_sequence_of_files?

The "dir()" version of the code is probably what you want. So do the loop once to scan the files, calling audioread, then get the length, then scan again to do the cropping. Make sure you save into a different folder so you don't permanently destroy your input sound files. In short:

filePattern = fullfile(inputFolder, '*.wav');
files = dir(filePattern)
minLength = inf;
for k = 1 : length(files)
    thisFileName = fullfile(inputFolder, files(k).name);
    [y, fs] = audioread(thisFileName);
    if length(y) > minLength
        maxLength = length(y);
    end
end
% Now scan again, doing the cropping
for k = 1 : length(files)
    thisFileName = fullfile(inputFolder, files(k).name);
    [y, fs] = audioread(thisFileName);
    y = y(1:minLength);
    outputFileName = fullfile(outputFolder, files(k).name);
    audiowrite(...........
end

etc. Or something like that. Of course you need to assign inputFolder and outputFolder to some actual folders on your drive.

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MATLAB: How to select one by one .wav files from a directory

   projectdir = '/Users/Snorky/music';
   dirinfo = dir( fullfile(projectdir, '*.wav') );
   numfiles = length(dirinfo);
   for K = 1 : numfiles
      thisfile = fullfile(projectdir, dirinfo(K).name );
      thisdata = wavread(thisfile);
      now do whatever with this data
   end

MATLAB: Open a series of images and save them in another folder

See http://www.mathworks.com/matlabcentral/answers/13205#answer_18099 to format your code.

See the FAQ to process a sequence of images: http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

You need to have two folder variables, one for input, and one for output. And you need two base file names, one for input and one for output. Then use full file to create two filenames:

fullInputFileName = fullfile(inputFolder, baseInputFileName);
fullOutputFileName = fullfile(outputFolder, baseOutputFileName);

baseInputFileName would be files(k).name.

See full demo below:

% Copies all the files from one folder to another folder.
clc;    % Clear the command window.
workspace;  % Make sure the workspace panel is showing.
format compact;
% Define input and output folders.
% CHANGE THESE FOLDER NAMES!!!!!!
inputFolder = pwd;
outputFolder = uigetdir(pwd);
if strcmp(outputFolder, inputFolder)
  errorMessage = sprintf('Error: the output folder must be different than the input folder');
  uiwait(warndlg(errorMessage));
  return;
end
% Check to see that both folders exist.
if ~isdir(inputFolder)
  errorMessage = sprintf('Error: The following input folder does not exist:\n%s', inputFolder);
  uiwait(warndlg(errorMessage));
  return;
end
if ~isdir(outputFolder)
  errorMessage = sprintf('Error: The following output folder does not exist:\n%s', outputFolder);
  uiwait(warndlg(errorMessage));
  return;
end
% Get a list of files to copy.
filePattern = fullfile(inputFolder, '*.*'); % All files.
% filePattern = fullfile(inputFolder, '*.m'); % m-files.
fileNamesToTransfer = dir(filePattern);
numFiles = length(fileNamesToTransfer);
% Do the copying.
for k = 1 : numFiles
  % Get the base file name.
  baseFileName = fileNamesToTransfer(k).name;
  % Create the full input and output filenames.
  fullInputFileName = fullfile(inputFolder, baseFileName);
  fullOutputFileName = fullfile(outputFolder, baseFileName);
  fprintf(1, 'Now copying file #%d of %d: %s to %s\n', ...
    k, numFiles, fullInputFileName, fullOutputFileName);
  copyfile(fullInputFileName, fullOutputFileName);
end
msgbox('Done copy files!', 'modal');

Best Answer

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