Curious about XviD/DivX Color Compared to MPEG-2 Color

[kalorx]

Hi all, the subject states my motivation. The reason for the curiosity lies in comparing (DVD) MPEG-2 color, which is, for lack of a better word, quite "rich," with XviD/DivX color, which is, for lack of a better word, "muted."

I can create DVD backups of perfect quality using XviD and DivX, save for that damned muted-color issue. I'm thinking it must have something to do with color space, but I'm under the impression that MPEG-2 and XviD/DivX both use YV12 almost exclusively. I could be wrong, of course, and most likely obviously am.

It's not like the color in my XviD/DivX videos goes away. It's just so... "not rich" compared to straight DVD MPEG-2. It's like going from a bright, sunny day to a rainy day: same color, just not as vibrant and alive.

I don't know if H.264 does this, which is strange, given that XviD, DivX, and H.264 are all based on MPEG-4 technology. I have yet to experiment more with H.264. However, to do that I need a PC devoted entirely to compression, seeing as H.264 backups at the quality I prefer require 48+ hours to compress (even with my high-end PC). (And worse, it requires XP Service Pack 2, which has on every XP PC I have ever owned flushed my OS down the toilet and required a reformat.)

I'm really concerned about this. I should have asked about this years ago, but only now am I getting off my lazy ass.

Thanks for any help!

Robert "KalorX" Aronson

[RogerWilco]

Hey.
I'm pretty much a newbie, but colormatrix may be what you are looking for:
http://avisynth.org.ru/docs/english/externalfilters/colormatrix.htm

I have also noticed that your decoder settings and the type of renderer you are using (overlay, VMR7, VMR9) can effect the output of the video. I was using overlay for xvid and VMR9 for dvds and I was seeing a big different in the color representation.

I'm sure you will get some better responses from the forum veterans, but I thought I'd chime in and try to help a little... :)

[sysKin]

How do you compare colour? If you're watching DVDs on software DVD players, they all have some extra saturation added. Look for picture profiles or something like that.

XviD doesn't "mute" the colour just like it doesn't make picture darker. It sounds like a difference in playback only.

[foxyshadis]

MeGUI and the other primary x264 frontends need .net 1 or 2, but x264 itself only needs an ia32/x64 platform and avisynth. You should be able to use virtualdub vfw, SUPER, or Mkvmagic, but I don't think any of them expose all the features of the command-line. Bummer about the SP2 business.

Otherwise rogerwilco's probably got the right idea, plus there's always ffdshow's color/gamma tweaks.

[setarip_old]

@kalorx

Hi!

If you've not already done so, you might try the following as an experiment, to narrow down the source of the difference you're seeing:

Make an .AVI (DivX or XviD compressed) from a commercial DVD that you own. Play a specific portion of the DVD with a software DVD player (VLC, WinDVD, PowerDVD, or similar). Then play the same portion of the .AVI with the same player - to see if there is still an observable difference in richness of color...

[kalorx]

Yeah, I'm starting to think it's a playback issue as well. I looked into FFDShow and my nVidia card's overlay settings, and found that FFDShow doesn't seem to affect my DVD playback (probably because its MPEG-2 function is disabled). I'm not sure where I'm going by telling you that (it's really late and I'm tired), but I present it to you anyway.

Actually, I think sometimes it's purely psychological -- as if I'm being driven (or have been driven) insane or something. Sometimes in shot-by-shot comparison the DVD seems brighter, while at other times the AVI or MKV seems brighter.

That colormatrix suggestion seems like it could really be onto something, as the website even mentioned something about a "slight difference in brightness."

Also, as for the software DVD players adding saturation, my nVidia overlay settings already automatically pump up the saturation by 14%.

Another issue could simply be bitrate: plain old visual quality. Source video is always going to look cleaner than its compressed form; the question is where visual cleaniness gives way to actual differences in playback.

Now I must sleep before I continue to ramble aimlessly.

Oh yes, I forgot: what is the difference between overlay, VMR7, and VMR9? How do you switch between them? I've heard mention of the latter two, but never much about them. As for overlay, I thought it was the universal form of hardware accelerated presentation.

[fight2win]

how to know when to use colormatrix in megui?

[MetalPhreak]

@fight2win
When the repotred colorimetry in DGIndex is ITU-R BT.709 or SMPTE 240M.
Some people say only when you see a change in color in your encode, but ClorMatrix has become standard issue in my encodes and things look better than ever.

[Teegedeck]

Colormatrix() should be your first filter, directly after mpeg2source("..."), so it can autodetect what (if any) transformation is necessary. I don't know how this is handled in MeGUI-generated scripts, though. Better check it out.

[kalorx]

Where in DGIndex does it report the colorimetry? I've been looking, but I can't find it...

[shon3i]

http://img219.imageshack.us/img219/9180/dgindex6vf.jpg
Ofcourse i using lastest beta DGIndex 1.47b4

[kalorx]

Thanks. I'm apparently using an out-of-date version of DGIndex...