[MPlayer-users] Re: [-] Re: divx 6

[Matthias Wieser]

Am Mittwoch, 3. Mai 2006 18:00 schrieb Rich Felker:
> On Wed, May 03, 2006 at 11:30:17AM +0200, Matthias Wieser wrote:
> > Am Dienstag, 2. Mai 2006 16:48 schrieb Rich Felker:
> > > On Tue, May 02, 2006 at 10:35:45AM +0200, Matthias Wieser wrote:
> > > > >>
> > > > >> I'm subscribed to all of those. URL?
> > > > >
> > > > > Not my job. Go read it yourself.
> > > >
> > > > YOU claim that there have been testing fallacies which doom9
> > > > refused to acknowledge. I followed the disussion and did not see
> > > > those. Others on lis list did not see them, too. So either prove
> > > > your claim or stop to allege that others are liars or did not read
> > > > the discussion.
> > >
> > > Apparently you're just as stupid as doom9 himself and don't
> > > understand the words IDCT mismatch.
> >
> > The IDCT topic has been discussed to death. This effect is way to small
> > to explain the worse quality (in comparison to xvid, divx) of lavc. You
> > have not been able to show that the differences are so large that they
> > matter.
>
> It's not my job to show that they matter. If doom9 is going to use the
> wrong IDCT it's HIS JOB to show that there's no difference.

He has done so. He even discussed this topic with the mplayer developers. He 
said there was no visible difference between both decoders. If you think he 
lied, please back up your insults. Screenshots are not so hard to make.


> I have no evidence that the quality differences in doom9's test came
> from IDCT discrepency, but the types of errors look VERY SIMILAR
> visually to the IDCT discrepency problem described on the ffmpeg-devel
> list with XVID.

No, he additionally used lavc to decode the lavc mpeg4 video and the quality 
problems (only little detail, blocks) still were there. If you think he 
lied, provide screenshots. Those quality differences have more probably 
been caused by inferior bframe support and rate control.


> > > Or the fact that doom9 was using broken windows tools (with possibly
> > > different semantics and bugs)
> >
> > Which bug numbers are you refering to? Or just plain FUD?
>
> Huh?

In which way broken? Bug number? Why did those alleged bugs only make lavc 
look worse and not xvid, too? Again: Back up your claims.


> > > to do the
> > > lavc encode rather than using the mencoder commandline he was given,
> > > and HIDING this fact from everyone.
> >
> > 1. HINT: Doom9 did a codec comparison (=> libav codec), not a video
> > tool (mencoder) comparison. That's why they call it "Codec shoot-out
> > 2005".
>
> There are exactly two programs with which lavc encoding can be tested
> validly: ffmpeg and mencoder. ffdshow, which I believe doom9 used, is
> a MODIFIED version of libavcodec with DIFFERENT DEFAULTS and has
> historically had bugs and misbehavior that made it produce bad output.
> We do not trust it.

Historically as in "xvid and divx are slow and bad"? You could always 
produce an lavc encode of Matrix with the given options that looks better 
than the doom9 version to back up your claims...


> In any case, doom9 was misleading from the very beginning about what
> software he was using, etc.

Where did he say that he is going to use mencoder? URL?
In his mails and in the codec comparison he clearly states what tools he is 
using to produce the videos.

> He was intentionally being evasive because 
> he knew his procedures were controversial and didn't want to admit it.

... :-)

> > 3. They used MP4 format:
> >    "To level the MPEG-4 playfield somewhat, this year all MPEG-4 codecs
> > will be using the MP4 container. Non MPEG-4 codecs will use the AVI
> > container or their native container."  (Does mencoder 1.0pre7 support
> > MP4? :-)
>
> The container is absolutely irrelevant to testing codecs. If he really 
> cared he could have remuxed into .mp4 with another program, but the
> very fact that he wanted to use .mp4 proves his technical
> incompetence.

Sure, people using MP4 are technical incompetent...

> > 4. They are not HIDING anything but they clearly state what software
> > they used:
> > 	"To encode I used the following software:
> > 	 DGIndex 1.4.5 & DGDecode
> > 	 AviSynth 2.55 for frameserving (avs2yuv doesn't support 2.56)
> > 	 VirtualDub 1.6.11 for VfW encoding
> > 	 Nandub 1.0 RC2 lumafix to multiplex AVI
> > 	 Mp4box CSV dated November 24th to multiplex MP4"
>
> I'm talking about what he revealed at the time when we initially
> questioned his methodology, not in the end.

URL!

       Matthias