How to read a yuv (or avi file) into matlab for video processing

What code should i insert above the code below which reads a yuv file (but if not possible, an avi file) for the following video processing. The code below is an algorithm that performs motion compensation. What are the output of this code?

% convert images to grayscale
    %f1 = 0.2989*f1(:,:,1) + 0.5870*f1(:,:,2) + 0.1140*f1(:,:,3);
    %f2 = 0.2989*f2(:,:,1) + 0.5870*f2(:,:,2) + 0.1140*f2(:,:,3);

      [height width] = size(f1); %size of first frame
      N = 16;  % blocksize

      mvx=[]; mvy=[]; ii = 1; fp = uint8(zeros(height,width));
      for i = 1:N:height
          jj = 1;
          for j = 1:N:width %for every block in the anchor frame
              MAD_min = 256*N*N
              MAD = MAD_min
              dx = 0
              dy = 0 
              for k = -R:1:R  % defines search range
                  for l = -R:1:R %defines search range, for every search candidate
                      if ~(i+k<=0 | j+l<=0 | i+k+N-1>height | j+l+N-1>width) % if inside boundary
                          MAD = sum(sum(abs(f1(i:i+N-1,j:j+N-1)-f2(i+k:i+k+N-1,j+l:j+l+N-1))))
                          if MAD < MAD_min
                              MAD_min = MAD
                              dy = k
                              dx = l
                          else
                              MAD = MAD_min
                              dx = dx
                              dy = dy
                          end
                      else
                          MAD = MAD_min
                          dx = dx
                          dy = dy
                      end
                      % calculate MAD for this candidate
                  end
              end
              %put the best matching block in the predicted image
              fp(i:i+N-1,j:j+N-1) = f2(i+dy:i+dy+N-1,j+dx:j+dx+N-1);
              mvx(ii,jj) = dx;
              mvy(ii,jj) = dy; %record the estimated MV
              jj = jj + 1
          end
          ii = ii + 1
      end
      figure; imshow(f1); title('anchor image');
      figure; imshow(f2); title('target image');
      figure; imshow(fp); title('predicted image');
      figure; imshow(f1-fp); title('prediction image error');
      figure; quiver(mvx,mvy); axis ij;

      f11 = double(f1); fpp = double(fp);
      err = 0;
      for c1 = 1:height
          for c2 = 1:width
              err = err + (f11(c1,c2) - fpp(c1,c2))^2;
          end
      end
      mse = err/(height*width);
      psnr = 10*log10((pk^2)/mse);
      pk = 255; %double(max(max(f1)));

      fprintf('PSNR = %f dB\n',psnr);

[Thien Thu Ngo]

What is R in this code?

[Walter Roberson]

R is a value passed in by the user, to the function version of this code, such as is shown at https://www.mathworks.com/matlabcentral/answers/29853-getting-an-error-subscript-indices-must-either-be-real-positive-integers-or-logicals

[Walter Roberson]

For 4:2:0 videos see https://www.mathworks.com/matlabcentral/fileexchange/59497-read-yuv-videos-and-extract-the-frames

See also https://www.mathworks.com/matlabcentral/fileexchange/36417-yuv-files-reading-and-converting and http://www.mathworks.com/matlabcentral/fileexchange/11318-transform-yuv-file

Answer 1

[Image Analyst]

Check out the VideoReader() class.

Answer 2

[Knut]

The weights in the top of your code seems to be the Y-weights in standard YCbCr: https://en.wikipedia.org/wiki/YUV

Thus it is probably written to accept "rgb" as input and generate a luma mixture for processing.

I don't know that there is a single standardized YUV video format (it could have subsampled chroma or not, interleaved or planar color components etc). Thus you need to figure out your YUV video format, possibly use fopen/fread/fclose to read each frame into memory, discard the U and V planes and feed the Y plane directly into line#5 of your script.