[MPlayer-users] Re: [POOL] Moderate some users (was: Re: [-] Re: divx 6)

[Vladimir Mosgalin]

Hi Matthias Wieser!

 On 2006.05.08 at 14:28:28 +0200, Matthias Wieser wrote next:

> Regarding image quality it's at least an indication.

If you believe it, I don't care. But in that case don't use it as an
argument.

> > 0.1 dB improvement - I can only laugh at that. Even 0.5 dB difference in
> > PSNR doesn't mean that one of the encoded version looks better.
> 
> You are free to invent a better metric. I have suggested to use SSIM.

I don't want to invent anything. Right now, I will just beleive my eyes.

> > I've seen so many cases when psnr and my eye tell me opposite, so now I
> > don't even try to compare psnr.
> 
> Nobody forces you to compare psnr. Just do your own gmc tests.

In fact, I did. And I posted about it in this thread.

---
As about XVID's GMC, I completely agree that it isn't useful feature. I
tested it quite a lot on different material, including the one that
theoretically should get improvement from gmc, on med/high/very high
bitrates. Well, what should I say, it sucks. Maybe it helps a bit in
some cases, but usually it just eats some bitrate. On every scene it
proved to be useless. As for doing complete dvd-rip with gmc option,
just forget about it - the best you will get is picture with the same
quality. Or it can decrease quality a bit (more likely on medium
bitrate). Most often you'll just get picture that's a bit different, but
you won't be able to see _any_ improvement.

Maybe in a very short scene with some kind of artificial pan/zoom it
would help you just a bit, if your bitrate is low. But on regular real
life or anime contents, don't turn it on.

PS I don't know, maybe it's just xvid's implementation is bad. But since
xvid is the best mpeg4 encoder out there right now, I'd say it's not
useful at all.
---

-- 

Vladimir