[FFmpeg-devel] [PATCH] Fix mlib DCT routine in dsputil

[Michael Niedermayer]

On Fri, Mar 28, 2008 at 05:01:38AM +0100, Michael Niedermayer wrote:
> On Thu, Mar 27, 2008 at 10:33:20PM -0400, Albert Lee wrote:
> > 
> > On Thu, 2008-03-27 at 03:05 +0100, Michael Niedermayer wrote:
> > > On Wed, Mar 26, 2008 at 04:32:44PM -0400, Albert Lee wrote:
> > > > Hi,
> > > > 
> > > > 
> > > > The ff_fdct_mlib() in dsputil has been broken for a long time; it
> > > > assumes the mediaLib DCT scales its output by 8 (as libjpeg's does).
> > > > This results in a well-known "green tint" problem. The attached patch
> > > > adds the scaling.
> > > > 
> > > > I'm also attaching the email from the mediaLib engineer who proposed the
> > > > fix.
> > > 
> > > Could you try to play the following file and tell us if it decodes without
> > > artifacts on mlib?
> > > 
> > > http://samples.mplayerhq.hu/Divx4-bugs/Lorenna_McKennit-Mummers_Dance-Mononoke_Hime-gabucino.avi
> > > 
> > 
> > Oh great, an AMV. Yeah, it looks fine. There was an awful lot of green in it to begin with, though.
> 
> green? You mean there are green blocks in there?
> Does it look different when decoded with -idct 2 ?
> 
> If you cant see a difference iam very interrested in the output of tiny_psnr
> from the 2 raw yuvs (-f rawvideo) generated with -idct 2 and 6 of this video.
> 
> Also is this sparc or x86 ?

And if it is sparc then iam also interrested how this video looks with -idct 18 ?
And of course what the speed difference is between -idct 18 and 6

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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