[MPlayer-dev-eng] synch to x264 r50 / mencgen

[Romain Dolbeau]

Loren Merritt wrote:

> It looks like mencgen is using the "Y", "U", and "V" PSNR fields. 

Yep, it is. Then recompute All using the lavc formula, which give
about the same results as the All from x264. I hoped it would
make the PSNR sort of comparable (isn't it all about "my PSNR is
bigger than yours" ? :-)

 > Don't.
> They are completely bogus, and will favor bad rate-control decisions.
> (I didn't manage to convince the x264 maintainers to remove them, since 
> the H.264 reference codec uses the same broken metrics.)
> The only correct PSNR value reported is "Global".

Could you explain the differences between them ? more important,
are Global and All giving the same order when sorting ? After all,
that's all mencgen care about.

> Other nitpicks with the current mencgen:
> It has two entries for cabacidc=1, and none for cabacidc=2. (Not that 
> I've ever seen cabacidc=2 help.)

fixed

> It doesn't try frameref>3. I see noticeable improvements all the way up 
> to frameref=15.

fixed

I'll add scenecut as soon as your patch is commited.

> Heh. I have here a run of 5000 lavc option sets for each of 3 source 
> videos...

Oh, it's "my run is bigger than yours" then :-) Well, I've done runs
in the tens of thousands with that tool :-)

-- 
Romain Dolbeau
<dolbeau at caps-entreprise.com>