b@2: function [] = batchresample(foldername, fsnew, bitdepthnew)
b@2: % BATCHRESAMPLE converts sample rate of all files in folder. 
b@2: % 
b@0: % by Brecht De Man at Centre for Digital Music on 13 April 2014
b@0: 
b@2:     if nargin < 2
b@2:         fsnew = 96000; 
b@2:     end
b@0: 
b@2:     if nargin < 3
b@2:         bitdepthnew = 24;
b@0:     end
b@8:     
b@0:     % go over all wav files in this folder
b@8:     files = dir([foldername '/*.wav']);
b@0: 
b@0:     % remove hidden files from list
b@0:     % see http://www.mathworks.co.uk/matlabcentral/newsreader/view_thread/258220
b@0:     for k = length(files):-1:1
b@0:         fname = files(k).name;
b@0:         if fname(1) == '.'
b@2:             files(k) = [];
b@0:         end
b@0:     end
b@0: 
b@0:     for k=1:length(files)
b@8:             info     = audioinfo([foldername '/' files(k).name]); 
b@2:             bitdepth = info.BitsPerSample; 
b@2:             fs       = info.SampleRate; 
b@0:             
b@2:             if fs==fsnew && bitdepth == bitdepthnew
b@2:                 disp([files(k).name ' already at ' num2str(fs) ' Hz, ' num2str(bitdepth) ' bit.']);
b@0:             else
b@8:                 [audio,fs] = audioread([foldername '/' files(k).name]); % read audio
b@2:                 disp([files(k).name ' was ' num2str(fs) ' Hz, ' num2str(bitdepth) ' bit.']);
b@2:                 if fs ~= fsnew
b@12:                     %audio = resample(audio, fsnew, fs);
b@12:                     
b@12:                     % exactly N seconds long
b@12:                     audio = [audio; zeros(fs - mod(size(audio,1), fs), size(audio, 2))];
b@12:                     
b@12:                     H = dsp.FIRRateConverter('InterpolationFactor', fsnew, 'DecimationFactor', fs);
b@12:                     audio = step(H, audio); % resample
b@2:                 end
b@8:                 audiowrite([foldername '/' files(k).name], audio/max(max(abs(audio))), ...
b@12:                     fsnew, 'BitsPerSample', bitdepthnew); % peak normalised! 
b@0:             end
b@0:     end
b@0: 
b@0: end