[MEncoder-users] from [divx-whatever-foo-bar] to theora

[D Richard Felker III]

On Sat, Mar 05, 2005 at 08:01:59PM +0100, Rakotomandimby (R12y) Mihamina wrote:
> On Sat, 2005-03-05 at 10:11 -0500, D Richard Felker III wrote:
> > On Sat, Mar 05, 2005 at 02:29:14PM +0100, Rakotomandimby (R12y) Mihamina wrote:
> 
> > You shouldn't. It's lies and propaganda. Read the archives on the
> > mplayer lists if you want to know why.
> 
> I found _no_ messages indicating theora sucks.

Look harder. But, see below for a better explanation of what I meant..

> > All this will do is convince people theora sucks, since converting
> > ALWAYS lowers quality no matter what codecs you're using.
> 
> Converting lowers quality: I agree with you.

Then why do you want to do it? All you'll do is make your precious
theora look bad if you release converted (and thus lower-quality)
files as theora...

> Theora sucks: I dont. But if you have some links to show me, I will read
> them carefully.

OK, there are two issues at hand. One is whether theora sucks, and the
other is whether you should be trying to convert everything (or
"convert" everyone) to theora like it's some kinda religion.

I'll address the latter first, since that's what I was actually
commenting about when I said the thing about lies and propaganda. The
Xiph people go around promoting theora is if it had some major
ideological advantage over other codecs (particularly mpeg4). They
claim it is non-patent-encumbered and thus "more free". This is a
blatent lie. Virtually every single patented algorithm used in mpeg*
codecs is also used in theora. Now, by prior art and obviousness, ALL
of these patents are blatently invalid and should be ignored. But the
point is that as far as patents go, theora is on equal ground with all
other modern codecs: either all of them infringe, or none of them do.
This issue has been discussed numerous times on the mplayer and ffmpeg
lists, and all the codec experts seem to agree.

Secondly there's the issue of whether theora sucks. I haven't used
theora so I can't say one way or the other. It's widely agreed that
vp3 is comparable to mpeg1 (yes, ONE) in compression, and theora is
basically just a repackaging of vp3 with a few new features, according
to my understanding. If you want to claim it's good with facts (e.g.
psnr comparison or extensive double-blind test results*) that's fine.
But most people are very doubtful..

> > None, mencoder does not support the theora codec for encoding.
> 
> Ok. I guess that's because the dev team thinks it's not a good format?
> Or is it just a matter of time?

I see no reason why it couldn't be included if someone submits a
patch. But we have no interest in doing it ourselves.

Rich

(*) For double-blind testing with video, it's not easy.. All possible
post-processing must be considered too. Otherwise idiotic codecs that
lose a lot more information but blur everything to cover up artifacts
will win with most viewers..