视频编解码质量评价---BDBR与BD-PSNR

梦里梦外; 2022-06-06 03:57 192阅读 0赞

Bjøntegaard delta bit rate (BDBR) 表示了在同样的客观质量下，两种方法的码率节省情况(Rate/distortion curves 画一条水平线)

Bjøntegaard delta peak signal-to-noise rate (BD-PSNR)表示了在给定的同等码率下，两种方法的PSNR-Y的差异(Rate/distortion curves 画一条垂直线)。

参考：[点击打开链接][Link 1]

matlab代码如下：

程序运行结果:

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testBjontegaard.m

% test Bjontegaard metric
    
    % 测试例子
    R1 = [686.760000000000;309.580000000000;157.110000000000;85.9500000000000];
    R2 = [893.340000000000;407.800000000000;204.930000000000;112.750000000000];
    PSNR1 = [40.2800000000000;37.1800000000000;34.2400000000000;31.4200000000000];
    PSNR2 = [40.3900000000000;37.2100000000000;34.1700000000000;31.2400000000000];
    
    [row,col] = size(R1);
    %预分配空间
    rate1=zeros(1,row);
    psnr1=zeros(1,row);
    rate2=zeros(1,row);
    psnr2=zeros(1,row);
    
    % 绘制曲线1
    for i=1:row          
            rate1(:,i) = R1(i,1);
            psnr1(:,i) = PSNR1(i,1);
    end
    plot(rate1,psnr1,'r-*');
    xlabel('Rate/kbps');
    ylabel('PSNR/dB');
    grid on;
    hold on;
    
    % 绘制曲线2
    for i=1:row          
        rate2(:,i)=R2(i,1);
        psnr2(:,i)=PSNR2(i,1);
    end
    plot(rate2,psnr2,'b-+');
    
    title('率失真曲线');
    legend('曲线1','曲线2',4);    %最后一个参数，1~4表示位置
     
    % 计算BDPSNR：
    % Bj?ntegaard delta bit rate (BDBR) 表示了在同样的客观质量下，
    % 两种方法的码率节省情况(Rate/distortion curves 画一条水平线)
    avg_diff_psnr = bjontegaard(R1,PSNR1,R2,PSNR2,'dsnr');
    
    % 计算BDBR：(注意结果是变化百分比)
    % Bj?ntegaard delta peak signal-to-noise rate (BD-PSNR)表示了在
    % 给定的同等码率下，两种方法的PSNR-Y的差异(Rate/distortion curves 画一条垂直线)。
    avg_diff_bitrate = bjontegaard(R1,PSNR1,R2,PSNR2,'rate');

bjontegaard.m

function avg_diff = bjontegaard(R1,PSNR1,R2,PSNR2,mode)
    
    %BJONTEGAARD    Bjontegaard metric calculation
    %   Bjontegaard's metric allows to compute the average gain in PSNR or the
    %   average per cent saving in bitrate between two rate-distortion
    %   curves [1].
    %   Differently from the avsnr software package or VCEG Excel [2] plugin this
    %   tool enables Bjontegaard's metric computation also with more than 4 RD
    %   points.
    %
    %   R1,PSNR1 - RD points for curve 1
    %   R2,PSNR2 - RD points for curve 2
    %   mode - 
    %       'dsnr' - average PSNR difference
    %       'rate' - percentage of bitrate saving between data set 1 and
    %                data set 2
    %
    %   avg_diff - the calculated Bjontegaard metric ('dsnr' or 'rate')
    %   
    %   (c) 2010 Giuseppe Valenzise
    %
    %   References:
    %
    %   [1] G. Bjontegaard, Calculation of average PSNR differences between
    %       RD-curves (VCEG-M33)
    %   [2] S. Pateux, J. Jung, An excel add-in for computing Bjontegaard metric and
    %       its evolution
    
    % convert rates in logarithmic units
    lR1 = log(R1);
    lR2 = log(R2);
    
    switch lower(mode)
        case 'dsnr'
            % PSNR method
            p1 = polyfit(lR1,PSNR1,3);
            p2 = polyfit(lR2,PSNR2,3);
    
            % integration interval
            min_int = min([lR1; lR2]);
            max_int = max([lR1; lR2]);
    
            % find integral
            p_int1 = polyint(p1);
            p_int2 = polyint(p2);
    
            int1 = polyval(p_int1, max_int) - polyval(p_int1, min_int);
            int2 = polyval(p_int2, max_int) - polyval(p_int2, min_int);
    
            % find avg diff
            avg_diff = (int2-int1)/(max_int-min_int);
    
        case 'rate'
            % rate method
            p1 = polyfit(PSNR1,lR1,3);
            p2 = polyfit(PSNR2,lR2,3);
    
            % integration interval
            min_int = min([PSNR1; PSNR2]);
            max_int = max([PSNR1; PSNR2]);
    
            % find integral
            p_int1 = polyint(p1);
            p_int2 = polyint(p2);
    
            int1 = polyval(p_int1, max_int) - polyval(p_int1, min_int);
            int2 = polyval(p_int2, max_int) - polyval(p_int2, min_int);
    
            % find avg diff
            avg_exp_diff = (int2-int1)/(max_int-min_int);
            avg_diff = (exp(avg_exp_diff)-1)*100;
    end

[Link 1]: http://cn.mathworks.com/matlabcentral/fileexchange/27798-bjontegaard-metric?focused=5154715&tab=function
[Center]: /images/20220606/14b1f67d6ac34c0c8c1d71c7b9f72370.png