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Re: [XviD-devel] Adaptive quantisation


To: xvid-devel@xxxxxxxx
Subject: Re: [XviD-devel] Adaptive quantisation
From: Dirk Knop <dknop@xxxxxxx>
Date: Sun, 04 Aug 2002 19:46:09 +0200
References: <Pine.LNX.4.21.0208041846370.31758-100000@lieb.math.uni-bonn.de> <Pine.LNX.4.21.0208041855560.31816-100000@lieb.math.uni-bonn.de> <20020804171957.GA12025@leloo>
User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0.1) Gecko/20020731

Hi,

Edouard Gomez wrote:

I don't  know if doom9 uses  to review open source  projects. But i've
never  seen reviews using  experimental code.  Koepi's builds  are cvs
snapshots + the  koepi's decision to include square me  or ... i would
have never used that to test a codec. I'm not criticizing koepi, I'm 
criticizing doom9's choice.

When someone has  to review the codec, it should  use a stable release
(or  the current  stable  snapshot,  as our  releases  are not  called
releases). I  would have laugh if  someone had tested  mozilla 2 years
ago with a  nightly build : "well mozilla is shit,  it crashes all the
time, renders  an html  page in  more than 1  minute..." or  tested my
speedtouch usb driver cvs when i'm working on new features...

Perhaps the solution is koepi proposes a stable - use for review
binary... don't know.


I made a "plain cvs" build too which we tested on SPR. It looked even worse. (Somehow EPZS is working even if it isn't coded "correctly". There were more visible blocks with PMVfast in these extreme situations.). That's the only thing I modified vs. the CVS. The first build (doom9 used the CVS+EPZS builds for a second test, respect for using other binaries too and check the results) was with hardcoded "cc kf" treatment, which he then told "not to recommend" (I totally agree there, it was just a proof-of-concept or better "let's see if it works" version). But the next builds he used (it was from CVS 01.08.) was "vanilla" with EPZS and looked better (the screenshots are from that encodings btw.). Well, we have to see if the old luma masking code is working better there. The curve treatment sure did a good job, but if the new algo is quantizing everything below/above some thresholds away the results are explainable.

Well, just wanted to mention that Doom9 tried to be fair, and he was kind of nice in his review.

And please, with all respect, the CVS is in a stable state for "vanilla" builds.

If anyone try to do a PSNR check and encode something with the "new" luma masking code, we could compare that to the "plain" version without the usage of adaptive quantization to see if the impact is that bad.

Don't get too picky on me(I once tried b-frames and took the build down when you aske me to, gruel!), if I made a failure I'd apologize, but I can't see where this was wrong.

Regards,
Koepi



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