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控制输出的标志定义
clc;close all;clear YES = 1; NO = 0; %YES表示输出该文件，请用户配置 yuv444_out_txt = 1; yuv444_out_yuv = 0; yuv422_out_txt = 0; yuv422_out_yuv = 0; yuv420_out_txt = 0; yuv420_out_yuv = 1;
filename = ‘Koala.jpg‘; filestr = filename(1:findstr(filename,‘.jpg‘)-1); filepath = [‘.\‘ filestr ‘out\‘] mkdir(filepath); filestr = [filepath filestr]; RGBimg =imread(filename); figure;imshow(RGBimg);
1）读入的照片由filename 配置，这里照片必须放在该目录下。如：filename = ‘Koala.jpg‘
2）filename找到字符串的起始位置。findstr(‘Koala.jpg‘,‘.jpg‘) = 6，所以就可以取到去掉后缀名的文件名
3）得到一个 .\文件名out\的目录
4）创建该目录
5）filestr = 目录+文件名，用于后面的数据输出，方便输出到 .\文件名out\目录下。这里 filestr = ‘.\Koalaout\Koala‘
YUVimg = rgb2ycbcr(RGBimg); %%% rgb -> yuv figure;imshow((YUVimg));
Y,U,V数据保留矩阵存储方式，方便后面的4:2:2，4:2:0采样，更加直观
[imgHeight imgWidth imgDim] = size(YUVimg); %% len = imgHeight*imgWidth*imgDim; yuvimout = zeros(1,len); Y = YUVimg(:,:,1); % Y 矩阵 U = YUVimg(:,:,2); % U 矩阵 V = YUVimg(:,:,3); % V 矩阵 Yvec = reshape(YUVimg(:,:,1)‘,1,[]); % 矩阵整理成行向量 Uvec = reshape(YUVimg(:,:,2)‘,1,[]); Vvec = reshape(YUVimg(:,:,3)‘,1,[]); yuvimout(1:3:len) = Yvec; yuvimout(2:3:len) = Uvec; yuvimout(3:3:len) = Vvec;
注意：reshape矩阵时，需要对结果做转置，保证是按行来将矩阵整理成行向量的
%%
% 输出图像的yuv数据到 .txt
%
if yuv444_out_txt == YES
filename = [filestr ‘_444.txt‘];
fid= fopen(filename,‘w‘);
fprintf(fid,‘%02x\n‘,yuvimout);
fclose(fid);
disp(‘yuv444_out_txt YES‘);
else
disp(‘yuv444_out_txt NO‘);
end
在本例中：filename = [filestr ‘_444.txt‘] = ‘.\Koalaout\Koala_444.txt‘
%%
% 输出图像的yuv数据到 .yuv
% 四个像素为：[Y0 U0 V0] [Y1 U1 V1] [Y2 U2 V2] [Y3 U3 V3]
%
% 存放的码流：[Y0 U0 V0] [Y1 U1 V1] [Y2 U2 V2] [Y3 U3 V3]
%
% 映射的像素: [Y0 U0 V0] [Y1 U1 V1] [Y2 U2 V2] [Y3 U3 V3]
if yuv444_out_yuv == YES
filename = [filestr ‘_444.yuv‘];
fid= fopen(filename,‘wb‘);
fwrite(fid,yuvimout,‘uint8‘);
fclose(fid);
disp(‘yuv444_out_yuv YES‘);
else
disp(‘yuv444_out_yuv NO‘);
end
%% % YUV4:4:4 -->> YUYV 4:2:2 % 四个像素为：[Y0 U0 V0] [Y1 U1 V1] [Y2 U2 V2] [Y3 U3 V3] % % 存放的码流：[Y0 U0] [Y1 V1] [Y2 U2] [Y3 V3] % % 映射的像素: [Y0 U0 V1] [Y1 U0 V1] [Y2 U2 V3] [Y3 U2 V3] %%% len = imgHeight*imgWidth+imgHeight*imgWidth/2+imgHeight*imgWidth/2; yuv422out = zeros(1,len); yuv422sampY = Y; yuv422sampU = U(:,1:2:size(U,2)); yuv422sampV = V(:,2:2:size(V,2)); yuv422out(1:2:len) = reshape(yuv422sampY‘,1,[]); %%% 注意要转置 yuv422out(2:4:len) = reshape(yuv422sampU‘,1,[]); yuv422out(4:4:len) = reshape(yuv422sampV‘,1,[]);
1）4:2:2模式是保留所有的Y，U,V是每间隔1列抽取抽样一个点，如代码中所示。
2）YUYV 4:2:2 packed 即像素值是 YU/YV 交替存储的模式。存放的码流：[Y0 U0] [Y1 V1] [Y2 U2] [Y3 V3]
%%
% 输出图像的yuv422数据到 .txt
%
if yuv422_out_txt == YES
filename = [filestr ‘_422.txt‘];
fid= fopen(filename,‘w‘);
fprintf(fid,‘%02x\n‘,yuv422out);
fclose(fid);
disp(‘yuv422_out_txt YES‘);
else
disp(‘yuv422_out_txt NO‘);
end
% output yuyv422 to .yuv file
if yuv422_out_yuv == YES
filename = [filestr ‘_422yuyv.yuv‘];
fid= fopen(filename,‘wb‘);
fwrite(fid,yuv422out,‘uint8‘);
fclose(fid);
disp(‘yuv422_out_yuv YES‘);
else
disp(‘yuv422_out_yuv NO‘);
end
%% % YUV4:4:4 -->> YUYV 4:2:0 % output yuyv422 to .yuv file % 第一行四个像素为：[Y0 U0 V0] [Y1 U1 V1] [Y2 U2 V2] [Y3 U3 V3] % 第二行四个像素为：[Y4 U4 V4] [Y5 U5 V5] [Y6 U6 V6] [Y7 U7 V7] % 4:2:0 采样 % 第一行采样像素为：[Y0 U0 ] [Y1 ] [Y2 U2 ] [Y3 ] % 第二行采样像素为：[Y4 V4] [Y5 ] [Y6 V6] [Y7 ] % 420yv12 planar 的存储码流: [Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7] [V4 V6] [U0 U2] % 映射的像素: [Y0 U0 V4] [Y1 U0 V4] [Y2 U2 V6] [Y3 U2 V6] % [Y4 U0 V4] [Y5 U0 V4] [Y6 U2 V6] [Y7 U2 V6] %%% len = imgHeight*imgWidth+imgHeight*imgWidth/4+imgHeight*imgWidth/4; yuv420out = []; yuv420sampY = Y; yuv420sampU = U(1:2:size(U,1),1:2:size(U,2)); yuv420sampV = V(2:2:size(V,1),1:2:size(V,2)); %%%yuv420out = [y v u] % yuv420 yv12 format yuv420out = [yuv420out reshape(yuv420sampY‘,1,[])]; %Y 注意要转置 yuv420out = [yuv420out reshape(yuv420sampV‘,1,[])]; %V yuv420out = [yuv420out reshape(yuv420sampU‘,1,[])]; %U
1）yuv420sampU = U(1:2:size(U,1),1:2:size(U,2)); 从图片的第一行开始 每间隔1行 和 每间隔1列 采样一个U
2）yuv420sampV = V(2:2:size(V,1),1:2:size(V,2)); 从图片的第二行开始 每间隔1行 和 每间隔1列 采样一个V
%%
% 输出图像的yuv422数据到 .txt
%
if yuv420_out_txt == YES
filename = [filestr ‘_420.txt‘];
fid= fopen(filename,‘w‘);
fprintf(fid,‘%02x\n‘,yuv420out);
fclose(fid);
disp(‘yuv420_out_txt YES‘);
else
disp(‘yuv420_out_txt NO‘);
end
% output yuyv420 to .yuv file
if yuv420_out_yuv == YES
filename = [filestr ‘_420yv12.yuv‘];
fid= fopen(filename,‘wb‘);
fwrite(fid,yuv420out,‘uint8‘);
fclose(fid);
disp(‘yuv420_out_yuv YES‘);
else
disp(‘yuv420_out_yuv NO‘);
end
观察命令输出，并等待关闭
disp(‘---program run susseed---‘); disp(‘---press any key to close all figure---‘); system(‘pause‘); close all;
打开输出的yuv文件查看图片
http://www.cnblogs.com/xkfz007/archive/2012/07/31/2616806.html
http://www.xuebuyuan.com/1541892.html
http://www.fourcc.org/yuv.php
代码链接：
http://pan.baidu.com/s/1pLMRcmB
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原文地址：http://www.cnblogs.com/hythink/p/5421720.html
