clear all;
s = wavread('sentence.wav');
fs = 16000;

% EXPANSION RATE
b=input('Enter the Required Percentage of Speed Increase\n');

% CHOOSING THE WINDOW LENGTH
winLen = 30 * 16;
l = length(s);
s = s';

% DETERMINING THE NO.OF SAMPLES TO BE SHIFTED 
shiftSamples = winLen*(b/2) / 100;

%LENGTH OF THE FINAL SENTENCE
e= ceil(l*(1+b/100))+ ceil(l/winLen)+100000;
s3 = zeros(1,e);
j1 = ceil(2*winLen/3);

tic
for a = 1 : ceil(winLen/3) : (length(s)-winLen)
      
   %To Find The Optimum Shift
   for i = 1 : winLen
      Ms(i) = s(i+a-1);
   end
   
   if (shiftSamples+40 > winLen)
      temp = winLen;
   else
      temp = shiftSamples+40;
   end
   
   if (shiftSamples-40 < 0)
      temp1 = 1;
   else
      temp1 = shiftSamples-40;
   end
   
   n=0;
   for j = temp1 : temp
      n = n + 1;
      MSE(n) = 0;
      for i = j+1 : winLen
         MSE(n) = MSE(n) + (Ms(i) - Ms((i-j)))^2;
      end
      MSE(n) = MSE(n)/(winLen - j+1);
   end
   
   [Y,I] = min(MSE);
   optShift = shiftSamples - (ceil(n/2) - I); 
   
   
   % TIME SHIFTING AND ADDING A WINDOW ONTO ITSELF
   s1 = zeros(1,(winLen+optShift));
   for i = 1 : winLen
      s1(i) = s(i+a-1);
   end

   for i = 1 : (optShift+winLen)
   	if i <= optShift
         s2(i) = s1(i);
      else
         s2(i) = s1(i) + s1(i-optShift);
      end
   end

   %CREATING THE FINAL SENTENCE
   j1 = j1 - ceil(2*winLen/3);
   for i = 1 : (winLen+optShift)
      j1=j1+1;
      s3(j1) = s3(j1) + s2(i);
   end
end
j1
t=toc
figure(1);
subplot(2,1,2);
plot(s);
subplot(2,1,2);
plot(s3);