音频数字水印

function chen=F2();
clear;
clc;
%read music
[M,fs,bits]=wavread('1.wav');
figure;subplot(2,2,3);plot(M);title('new audio');
len_Music=length(M);
%read watermarking picture
P=imread('1.jpg');
P=im2bw(P);
[m,n]=size(P)
 subplot(2,2,1);imshow(P);title('watermarking picture');
%original audio to 'm; segment
len_seg=floor(len_Music/m);
%beginning dwt 
%1)length of every segment  is len_seg
B=cell(len_seg,1);
k=0;
for i=1:m
    j=(k+1):(k+len_seg);
    B{i,1}=M(j,1);
    k=k+len_seg;
end
%2)embbing
D=0.0355;
NM=M;
for i=1:m
    [c,l]=wavedec(B{i,1},3,'db1');
    ca3=appcoef(c,l,'db1',3);
    cd3=detcoef(c,l,3);