clear all
 for i=1:30
   fname=sprintf('D:\\study\\音頻采樣\\noise22050hz\\%d.wav',i);
   x=wavread(fname);
   x=x(:,1);
   [c,l]=wavedec(x,3,'db4');
   ca=appcoef(c,l,'db4',3);%近似系數
   x=ca;
   enframex=enframe(x,128,64);%對信號x分幀處理，每幀有128個采樣點，相鄰幀之間有50%的疊加率
   [row,col]=size(enframex);%返回行，列，每一行代表一幀，每一列表示1到128個采樣點
   A=abs(enframex).^2;
   for j=1:row
     energy(j)=sum(A(j,:));
   end
    se=0;
   for j=1:row
       se=se+energy(j);
   end
   for j=1:row
       p(j)=energy(j)./se;
   end
   s=0;
   for j=1:row
     s=s+p(j).*log2(p(j));
   end
   Err=-s;
   swmErrzhuzhi(i,1)=mean(Err);
 end
  swmErrzhuzhi