[WM]: comparsion of MPEG compression on I frames & JPEG compression

[Anindya Sarkar <ani.great@gmail.com>]

Hi
  I  am interested in knowing the following:
1) say I have 100 raw image frames and I apply MPEG compression on them using a certain quality factor.. Once I have the MPEG video,
I apply MPEG decoder to get back the 100 frames..
2) I repeat the compression experiment using JPEG compression using the sam= e quality factor..

  Now if we compare the I frames in case 1 (MPEG) with the corrresponding frames in JPEG, then I guess that the frames should be
same (I guess what MPEG does to I frames is similar to JPEG only)..

 However, on comparing the values ,I found there were differences in the images (not visual but 10-15 difference in pixel values,
each pixel value i= s
8 bit 0-255)

 I was using MPEG-2 (standard code available from MPEG website) for MPEG compression and for JPEG I was using the imwrite command in
MATLAB..where w= e can specify what quality factor to use..

 So plz tell me on what u think the error is due to..

 Thanks
 Anindya


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