How to calculate the PSNR of video sequence?

Hi there,

I want to calculate the PSNR value between two videos. One video is original and another one is watermarked video. The watermarked video has some watermarked frame. I have calculated PSNR of each frame one at a time of both of the videos, and calsulate the average of it, but unfortunately I get the "Inf" value of PSNR.

Again, I have also tried to calculate the PSNR of exactly two videos. As a result, I got the PSNR of 40 dB. In fact, the result must be 99.99

Any help must be appreciated.

Thanks in advance.

The code I have written to calculate the PSNR of two idential videos

clc;

output_folder = 'D:\Matlab book and files\SLT\Akiyo_frames_journal';

vidObj1 = VideoReader('akiyo_cif_x264.mp4');

vidObj2 = VideoReader('akiyo_cif_x264_Copy.mp4');

EnumFrames=0;

Extframe = cell(1,300) ;

frame = cell(1,300) ;

numFrames1 = 0;

numFrames2 = 0;

while hasFrame(vidObj1)

F1 = readFrame(vidObj1);

numFrames1 = numFrames1 + 1;

frame{numFrames1} = F ;

numFrames1

while hasFrame(vidObj2)

F2 = readFrame(vidObj2);

numFrames2 = numFrames2 + 1;

Extframe{numFrames2}=F2;

end

numFrames2

for i= 1:300

Extframe{i}= getframe;

frame{i}= getframe;

fprintf ("The PSNR of frame %d = %.2f \n", i , psnr(frame2im(Extframe{i}),frame2im(frame{i})))

end

OUTPUT

The PSNR of frame 1 = Inf

The PSNR of frame 2 = Inf

The PSNR of frame 3 = Inf

The PSNR of frame 4 = Inf

The PSNR of frame 5 = Inf

The PSNR of frame 6 = Inf

The PSNR of frame 7 = Inf

The PSNR of frame 8 = Inf

The PSNR of frame 9 = Inf

The PSNR of frame 10 = Inf

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The PSNR of frame 300 = Inf