waveFile='singaporeIsAFinePlace.wav';
au=myAudioRead(waveFile); y=au.signal; fs=au.fs;
frameSize = 256;
overlap = 128;

y=y-mean(y);				% zero-mean substraction
frameMat=buffer2(y, frameSize, overlap);	% frame blocking
frameNum=size(frameMat, 2);			% no. of frames
volume=frame2volume(frameMat);
sumAbsDiff1=sum(abs(diff(frameMat)));
sumAbsDiff2=sum(abs(diff(diff(frameMat))));
sumAbsDiff3=sum(abs(diff(diff(diff(frameMat)))));
sumAbsDiff4=sum(abs(diff(diff(diff(diff(frameMat))))));

subplot(2,1,1);
time=(1:length(y))/fs;
plot(time, y); ylabel('Amplitude'); title('Waveform');
subplot(2,1,2);
frameTime=frame2sampleIndex(1:frameNum, frameSize, overlap)/fs;
plot(frameTime', [volume; sumAbsDiff1; sumAbsDiff2; sumAbsDiff3; sumAbsDiff4]', '.-');
legend('Volume', 'Order-1 diff', 'Order-2 diff', 'Order-3 diff', 'Order-4 diff');
xlabel('Time (sec)');