1.读入照片
控制输出的标志定义
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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;
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filename = 'Koala.jpg';
filestr = filename(1:findstr(filename,'.jpg')-1);
filepath = ['.\' filestr 'out\']
mkdir(filepath);
filestr = [filepath filestr];
RGBimg =imread(filename);
figure;imshow(RGBimg);
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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'
2. 调用matlab函数将rgb转换成yuv
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YUVimg = rgb2ycbcr(RGBimg); %%% rgb -> yuv
figure;imshow((YUVimg));
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3.分别取出YUV
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
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[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;
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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
4.输出YUV444的数据到文件
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%%
% 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
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在本例中：filename = [filestr '_444.txt'] = '.\Koalaout\Koala_444.txt'
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%%
% 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
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5.将 YUV4:4:4 转成 YUYV 4:2:2 packed
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%%
% 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,[]);
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说明：
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]
输出数据到文件
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%%
% 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
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6. 将 YUV4:4:4 转成 YV12 4:2:0 planar
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%%
% 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
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说明：
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
数据数据到文件
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%%
% 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
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观察命令输出，并等待关闭
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disp('---program run susseed---');
disp('---press any key to close all figure---');
system('pause');
close all;
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打开输出的yuv文件查看图片
参考
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http://www.cnblogs.com/xkfz007/archive/2012/07/31/2616806.html
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http://www.xuebuyuan.com/1541892.html
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http://www.fourcc.org/yuv.php
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代码链接：
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http://pan.baidu.com/s/1pLMRcmB
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