matlab-pseudocode

function rmsLeveler % normalizes a set of files to all have the same RMS amplitude. Target % amplitude is either (1) matched to that of an existing wav file that you % specify, or (2) the maximum possible RMS that still avoids clipping. % % DEPENDS: cell2csv.m % http://www.mathworks.com/matlabcentral/fileexchange/4400-cell-array-to-csv-file-cell2csv-m

% % AUTHOR: Daniel McCloy (drmccloy@uw.edu) % LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 LICENSE: http://creativecommons.org/licenses/by/3.0/

%% load in list of wav file paths fprintf('\nSelect WAV files to normalize\n'); [fileNameArray,fileFolderPath,~] = uigetfile('*.wav','Select WAV files to normalize','MultiSelect','on'); pathList = cell(size(fileNameArray)); for k=1:length(fileNameArray) % convert the list of stimulus filenames into full file paths pathList{k} = strcat(fileFolderPath,fileNameArray{k}); end

%% read in WAV data and calculate RMS and clipping-safe scale factors fprintf('Reading WAV files...\n');

%preallocate RMS / maxAmp / maxScale vectors & cell array of wav data
rmsVec = zeros(length(pathList),1);
maxAmp = zeros(length(pathList),1);
wavData = cell(size(pathList));

% assuming all files are the same, take the bitrate from the first file
[~,bitrate] = wavread(pathList{1});

% Read each file, calculate its RMS ampl & max peak
for m=1:length(pathList)
    wavData{m} = wavread(pathList{m});
    rmsVec(m) = sqrt(sum(wavData{m}(:).^2)/length(wavData{m}(:)));
    maxAmp(m) = max(abs(wavData{m}(:)));
end

% the maximum factor by which we could scale each file without inducing clipping
maxScale = 0.999 ./ maxAmp;

% the maximum possible RMS level for each file without inducing clipping
maxRMS = maxScale .* rmsVec;

%% ask whether we're trying to match a target file or not rmsMode = input('\nEnter "1" to match RMS of another WAV file (you will be prompted for that file),\nor enter "2" to RMS level based only on your stimuli (maximize RMS but avoid clipping) >> '); if rmsMode == 1 % load in target WAV file that has the desired target RMS amplitude already fprintf('Select target WAV file that already has desired RMS level\n'); [targetFile,targetFolder,~] = uigetfile('*.wav','Select target WAV file to match RMS to:','MultiSelect','off'); targetPath = strcat(targetFolder,targetFile);

	% Read the target file and calculate its RMS amplitude
    targetWAV = wavread(targetPath);
    targetRMS = sqrt(sum(targetWAV(:).^2)/length(targetWAV(:)));

    if targetRMS > min(maxRMS)
	% clipping will happen
        clipVec = maxRMS < targetRMS;
        clipCount = sum(clipVec);
        allowClip = input(sprintf('WARNING: using this RMS target will cause clipping in %d of your files. Continue? [y/n] >> ', clipCount), 's');
    
        if strcmpi(allowClip,'n')
        % the user doesn't want clipping
            preventClip = input('Continue leveling to the max RMS value that still avoids clipping? [y/n] >> ', 's');

            if strcmpi(preventClip,'n')
            % the user gives up
                error('\nCancelling rmsManager: no files were RMS leveled.\n');
            else
            % the user RMS levels anyway, ignoring the target file
                fprintf('OK, continuing, but leveling to the max value that prevents clipping.');
        		targetRMS = min(maxRMS);
            end
        
        else
        % the user continues despite clipping, so we temporarily turn off the clipping warning and instead write out a list of the files that got clipped.
            disableWarn = warning('off','MATLAB:wavwrite:dataClipped');
            fprintf('OK, continuing, and writing a list of clipped files to the script folder.\n');
            clipList = cell(clipCount,1);
            n = 1;
            for p=1:length(clipVec)
                if clipVec(p) == 1
                    clipList{n} = pathList{p};
                    n=n+1;
                end
            end
            % write out the list of clipped files
            cell2csv('listOfClippedFiles.csv',clipList);
        end
    end

elseif rmsMode ~= 2
% user didn't pick a viable option
    error('\nYou did not push either 1 or 2\n')
else
% rmsMode is "2", meaning there is no target file. Thus we calculate the target RMS as the lowest of the maximum RMS levels (i.e., the only one that is safe for all files).
	targetRMS = min(maxRMS);
end

%% specify output folder fprintf('\nSelect output folder for normalized files:\n'); outputFolder = uigetdir(cd,'Select output folder for normalized files:');

%% rescale the files and write them out for k=1:length(pathList) temp = wavData{k}*targetRMS/rmsVec(k); outputFile = strcat(outputFolder,'/',fileNameArray{k}); wavwrite(temp,bitrate,outputFile); end

% write success message
if ~exist('clipList','var')
		clipList = [];
end
fprintf('Done! %d files normalized, %d of them were clipped.\n',length(pathList),length(clipList));

% re-enable warnings for wavwrite clipping:
if exist('disableWarn','var')
	warning(disableWarn);
end

end