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Old 30th December 2008, 20:07   #1  |  Link
KikeG
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VAQ and MPEG quantization matrix?

I've read that VAQ should only be used with H.263 quantization.

However I've tried using it with MPEG quantization and there's also a size advantage. On a 17 sec. clip of already encoded video of Monsters Inc., encoded at constant q=3, there's a 7'4% size advantage using H.2.63 and a 6,9% size advantage using a MPEG quantization matrix.

As I see VAQ increases quantizers in areas with higher detail. I don't understand why this works any different with a MPEG cqm. Maybe it is because with VAQ quality can suffer more in case of MPEG cqm?

Thanks.
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Old 30th December 2008, 20:07   #2  |  Link
Dark Shikari
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Quote:
Originally Posted by KikeG View Post
I've read that VAQ should only be used with H.263 quantization.
You read wrong.
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Old 30th December 2008, 20:23   #3  |  Link
KikeG
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I don't think I read wrong, however I didn't read it from you. Anyway, thanks for the clarification, it's what I wanted to know.
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Old 30th December 2008, 20:31   #4  |  Link
Dark Shikari
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Quote:
Originally Posted by KikeG View Post
I don't think I read wrong
One could define "reading something that is wrong" as reading wrong...
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Old 31st December 2008, 04:39   #5  |  Link
Sharktooth
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using a custom quantization matrix with VAQ may lead to unwanted results. but that depends on the matrix.
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Old 31st December 2008, 11:53   #6  |  Link
flebber
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Quote:
Originally Posted by Sharktooth View Post
using a custom quantization matrix with VAQ may lead to unwanted results. but that depends on the matrix.
Other than trial and error, is there anyway to predict when a matrix and VAQ combo will cause error?
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Old 31st December 2008, 12:12   #7  |  Link
KikeG
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In case of MPEG quantization matrix, what unwanted results?
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Old 31st December 2008, 14:39   #8  |  Link
Gromozeka
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Mpeg matrix with VAQ give good result, but VAQ with ZSM matrix jawor-a - very bad result
mpeg matrix q3 with VAQ very good too
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Old 16th February 2009, 11:48   #9  |  Link
henryho_hk
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Sharktooth, would you please share your opinion or experience of your MPEG-4 ASP Custom Matrices with VAQ? H.263 is really a bit too soft.
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Old 16th February 2009, 14:48   #10  |  Link
Sharktooth
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@henryho_hk: i no longer use xvid for my encodings since years.

@KikeG: i said CUSTOM quantization matrices (MPEG matrix is not "custom"...).
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Old 16th February 2009, 21:52   #11  |  Link
BigDid
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Quote:
Originally Posted by henryho_hk View Post
Sharktooth, would you please share your opinion or experience of your MPEG-4 ASP Custom Matrices with VAQ? H.263 is really a bit too soft.
Quote:
Originally Posted by Sharktooth View Post
@henryho_hk: i no longer use xvid for my encodings since years...
Hi,

I am actually testing some CQM (custom matrixes) to replace standard matrixes for xvid encoding; more in the different AutoGk threads..

When I will have finished my tests I could share my experience; Atm it is just an opinion

To the point, usually MPEG is a little more compressible than H263 and sharper but H263 is still excellent for anim or 3D-anim
So if you want sharp or more sharp, less compressible than H263 try Eqm V2 (AutoGk sharp) and Eqm V3 HR
If you want more compressible and still sharper than H263 try Eqm V3 LR and/or Eqm V3 ULR

My first tests shows that all CQM from Sharktooth behaves well with VAQ and that gives me the opportunity to thank him for all the worK done

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Last edited by BigDid; 17th February 2009 at 02:24.
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Old 17th February 2009, 03:48   #12  |  Link
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that was... unexpected, however im happy they dont screw up...
on a sidenote eqm v3 ULR is obsolete since LCD displays. the reason is the "artificial" sharpening becomes an issue with high-contrast displays.
it is still valid if you have a CRT monitor/TV though...
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Old 17th February 2009, 04:05   #13  |  Link
BigDid
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that was... unexpected, however im happy they dont screw up...
Hi Sharky, you're the man!

Quote:
... on a sidenote eqm v3 ULR is obsolete since LCD displays. the reason is the "artificial" sharpening becomes an issue with high-contrast displays...
I persist; have done side by side 1 comparison with Jawor 1cd and ULR, some differences, but both are usable for that kind of extreme compressibility (ULR_VAQ is more compressible than Jawor_VAQ), seems VAQ rubs the artificial sharpening (even if ringing or artifacts still present).

I have not tested your UHR and EHR but Didée 6o9 seems to give excellent results with VAQ.

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Old 17th February 2009, 13:01   #14  |  Link
henryho_hk
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Quote:
seems VAQ rubs the artificial sharpening
Perhaps VAQ saves enough bits to allow for lower quantizers.

I really hope that there will be XviD 1.2.2 which officially incorporates VAQ.
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