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 Doom9's Forum Unblock - statistical deblocking filter (blind)
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 23rd December 2007, 19:00 #1  |  Link Fizick AviSynth plugger     Join Date: Nov 2003 Location: Russia Posts: 2,183 Unblock - statistical deblocking filter (blind) I was need to deblock photo slides copy and discover interesting debloking program at: http://www.assassinationscience.com/...tella/unblock/ From the original paper: We don't have the original image, so we can't be sure that there isn't a sharp discontinuity in the original image that happens to lie right on the boundary. If we removed all discrepancies unconditionally, we would automatically blur out any such sharp edge that happens to unfortunately fall in the wrong place. It is impossible to avoid such an error in every possible case, but we can do so statistically. For any given image, the distribution of the magnitudes of the block boundary discontinuity errors will be determined by the amount of compression employed (the "quality factor"). By computing the distribution of boundary discrepancies across the entire image, and comparing it to the distribtuion of "discrepancies" calculated in the interior of the blocks, we can quantify, statistically, the amount to which the compression has introduced block artifacts. Now, what are we to do with these statistical distributions? A reasonable ansatz is that we should reduce each boundary discrepancy by an amount that will make the interior and boundary discrepancy distributions the same, as far as possible. it is first part of my message - i need in thread number for plugin doc
 24th December 2007, 16:19 #2  |  Link Soulhunter Bored...     Join Date: Apr 2003 Location: Unknown Posts: 2,812 Regarding the comparison... If Pegasus would interpolate the chroma like Unblock does, it would look much better! >.> Merry X-Mas n' Bye __________________ Visit my IRC channel Last edited by Soulhunter; 24th December 2007 at 22:30.
 24th December 2007, 21:18 #3  |  Link Fizick AviSynth plugger     Join Date: Nov 2003 Location: Russia Posts: 2,183 Plugin and doc is almost ready. But I try contact author for some question about chroma deblocking. I forget that X-mas is today In our country it is 7 january, but new year is 1 january too
25th December 2007, 01:59   #4  |  Link
redfordxx
Registered User

Join Date: Jan 2005
Location: Praha (not that one in Texas)
Posts: 863
Quote:
 Originally Posted by Fizick Plugin and doc is almost ready. But I try contact author for some question about chroma deblocking.
But it is only needed when you go away from YV12 --- otherwise is the chroma treated same as luma, right?
Quote:
 I forget that X-mas is today In our country it is 7 january, but new year is 1 january too
Yeah, as one friendof mine (came from somewhere around Vladivostok) told me, she starts shopping for "her" Xmas only after "our" Xmas, when there are the greatest sale prices;-)

Merry Xmas to all...

 25th December 2007, 02:40 #5  |  Link redfordxx Registered User   Join Date: Jan 2005 Location: Praha (not that one in Texas) Posts: 863 I read the paper. I really wonder how it is possible, that it works with lines treated independently... Moreover, I am little unsure in the part 3.5 of the paper...maybe my view is then wrong and needs correction: Is your goal JPEG or MPEG or both? In case of MPEG I think it could be interesting to incorporate weighting by quantizers (two adjacent blocks with different quantizer can differently contribute to the discrepancy). Interior discrepancy values will also depend on quantizer (higher q=smaller interior discrepancy, bigger boundary discrepancy). Also, error magnitude can be estimated using quantizer and matrix values.
 25th December 2007, 07:04 #6  |  Link Fizick AviSynth plugger     Join Date: Nov 2003 Location: Russia Posts: 2,183 redfordxx, no, weighting by quantizers will be incorporated in your filter, not in the Unblock it is blind like blindPP function. (it is not point what is better. There are many methods. Unblock is Unblock as is) __________________ My Avisynth plugins are now at http://avisynth.org.ru and mirror at http://avisynth.nl/users/fizick I usually do not provide a technical support in private messages.
25th December 2007, 14:12   #7  |  Link
Soulhunter
Bored...

Join Date: Apr 2003
Location: Unknown
Posts: 2,812
Quote:
 Originally Posted by redfordxx But it is only needed when you go away from YV12...
Chroma deblocking? No! Chromaupsampling? Yes! Just wanted to point out that the comparison on this page could give a false impression... Because the Unblock results have upsampled chroma but the Pegasus ones have not... The pointresized chroma of the Pegasus results, together with the global 2x pointresize, gives the impression that the Pegasus results look much more blocky than they really are... As this comparison is about deblocking and not about [relative easy to accomplish] chroma chromaupsampling, let us compare just the deblocking... ^^

Bye
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 25th December 2007, 19:30 #8  |  Link Fizick AviSynth plugger     Join Date: Nov 2003 Location: Russia Posts: 2,183 Released UnBlock version 1.1 __________________ My Avisynth plugins are now at http://avisynth.org.ru and mirror at http://avisynth.nl/users/fizick I usually do not provide a technical support in private messages.