YUV序列下采样以及彩色4:2:0与灰度4:0:0转换---基于matlab实现

我不是女神ヾ 2022-06-02 06:47 145阅读 0赞

1、YUV序列（4:2:0）下采样

matlab代码：

yuvDownSample.m

clear
    clc
    
    %% Read yuv from file
    yuvseq = 'kendo0.yuv';        % 输入yuv序列名称
    fid = fopen(yuvseq, 'r');
    
    row=1024;col=768;             % 输入yuv序列尺寸
    fnum=300;                     % 要转换的帧数
    
    Y=zeros(row,col,fnum);
    U=zeros(row/2,col/2,fnum);
    V=zeros(row/2,col/2,fnum);
    
    YY=zeros(row/4,col/4,fnum);   % 4倍下采样（除以4）
    UU=zeros(row/8,col/8,fnum);
    VV=zeros(row/8,col/8,fnum);
    
    for frame=1:fnum
        [Y(:,:,frame),count] = fread(fid,[row,col],'uchar');
        [U(:,:,frame),count1]=fread(fid,[row/2,col/2],'uchar');
        [V(:,:,frame),count2]=fread(fid,[row/2,col/2],'uchar');
        
         YY(:,:,frame) = Y(1:4:row,1:4:col,frame);
         UU(:,:,frame) = U(1:4:row/2,1:4:col/2,frame);
         VV(:,:,frame) = V(1:4:row/2,1:4:col/2,frame);
    end
    
    filename=sprintf('%s%s','downSample_',yuvseq);      % 下采样后输出yuv序列名称
    outfid=fopen(filename,'wb');
    
    for frame=1:fnum
        fwrite(outfid,YY(:,:,frame), 'uchar');
        fwrite(outfid,UU(:,:,frame), 'uchar');
        fwrite(outfid,VV(:,:,frame), 'uchar');
    end
    fclose(fid);
    fclose(outfid);

2、YUV序列（4:2:0）转换为灰度YUV序列（4:0:0）

主函数：main\_color2gray.m

function main_color2gary()
    
    % 帧数
    f=300;    
    % 参数downSample_kendo0.yuv为输入视频（4:2:0），
    % 参数downSample_kendo0_gray.yuv为转换输出的视频（4:0:0）
    % 参数f为转换帧数
    % 参数'downSample'表示输入视频的尺寸，可以进入color2gary内查看及设置。
    color2gary('downSample_kendo0.yuv','kendo0_gray.yuv',f,'downSample');

子函数：color2gray.m

function color2gary(fin,fout,fnum,frmsz)
    if isequal(frmsz,'qcif')
        fwid=176;
        fhei=144;
    elseif isequal(frmsz,'cif')
        fwid=352;
        fhei=288;
    elseif isequal(frmsz,'downSample')
        fwid=256;
        fhei=192;
    elseif isequal(frmsz,'1024x768')
        fwid=1024;
        fhei=768;
    elseif isequal(frmsz,'1280x720')
        fwid=1280;
        fhei=720;
    elseif isequal(frmsz,'1920x1080')
        fwid=1920;
        fhei=1080;
    elseif isequal(frmsz,'832x480')
        fwid=832;
        fhei=480;
    elseif isequal(frmsz,'roi')
        fwid=128;
        fhei=192;
    end
    rec=zeros(fhei,fwid,fnum);
    for f=1:fnum
        rec(:,:,f)=open420Y(fin,fwid,fhei,f);
    end
    saveY(rec,fout);

子函数：open420Y.m

function img=open420Y(fname,width,height,frame_idx)
    
    fid=fopen(fname,'r');
    fsize=width*height;
    frame_no=length(frame_idx);
    img=zeros(height,width,frame_no);
    for i=1:frame_no
        fseek(fid,(frame_idx(i)-1)*fsize*3/2,'bof');
        buf=fread(fid,fsize,'uint8');
        img(:,:,i)=double(reshape(buf,width,height).');
    end
    fclose(fid);

子函数： saveY .m

function saveY(img,fname)
    
    fid=fopen(fname,'w');
    [row,col,frm]=size(img);
    for i=1:frm
        buf=uint8(img(:,:,i).');
        count=fwrite(fid,buf,'uint8');
    end
    fclose(fid);

多视点视频序列下载地址： [http://www.tanimoto.nuee.nagoya-u.ac.jp/~fukushima/mpegftv/][http_www.tanimoto.nuee.nagoya-u.ac.jp_fukushima_mpegftv]  
  
![SouthEast][]

[http_www.tanimoto.nuee.nagoya-u.ac.jp_fukushima_mpegftv]: http://www.tanimoto.nuee.nagoya-u.ac.jp/~fukushima/mpegftv/
[SouthEast]: /images/20220602/036ab875e36746d7b75bb0c7195c10a1.png