How 2 get better color dither in MPG2 render?

fwtep wrote on 1/16/2006, 10:46 PM

Does anyone know any magic settings that will give a better bit depth to the color in an MPG2 render for DVD? I have a video (3D animation) that is very soft (think "It Happened One Night" but in color), which looks fine every step of the way except the MPG2 render, which has pretty noticable banding in the gradients. There's nothing I can do about the original image-- I have the look I want for it-- and even at DV bit-depth it looks fine, so I'm hoping there's something I can set in the Video or Advanced video settings in the Main Concept custom options.

One more thing: The fix, assuming there is one, can't be something that will make the DVD finicky about which players it will work in. I never have a problem with compatibility and I don't want to risk starting now. By the way, I've been rendering at a constant bit rate of 8,000,000. I've tried setting it higher but it warns me that there might be compatibility issues.

The video is NTSC resolution, progressive, 23.976 fps and it's only 2 minutes long, so file size isn't an issue-- there's plenty of room available on the DVD. (At the bit rate I compress at, the file is about 167mb.)

Thanks,
Fred

Comments

johnmeyer wrote on 1/16/2006, 11:07 PM

Which MPEG template are you using?

fwtep wrote on 1/16/2006, 11:08 PM

DVD Architect 24p NTSC, modified for a Constant Bitrate of 8,000,000.

farss wrote on 1/16/2006, 11:32 PM

Somehow I don't thin this has anything to do with bit rate.
What format is the original animation in?
I suspect what you are seeing is problems due to converting between RGB and YUV (or the other way around or maybe it's going thru that transition more than once)
Bob.

fwtep wrote on 1/16/2006, 11:35 PM

Original frames are 32bit Targas. Compositing is in After Effects and saved out as Microsoft DV. I know that's not the best codec, but at least I'm not getting the banding there-- it looks fine.

As far as bit rate, I'm not necessarily saying that's what the prpblem is, I just pointed out the bit rate I was using so people's first suggestion wouldn't be "raise the bit rate."

farss wrote on 1/17/2006, 12:14 AM

OK,
so you've bought the DV file(s) into a Vegas NTSC project and they looks OK?
Try this, lower the track opacity to 99% to force Vegas to recompress and see if they still look OK. Reason being that Vegas works in RGB NOT YUV, does it still look OK?

So you encode to mpeg-2 and author a DVD and when you play the DVD back is that the first time you notice this banding problem?

What about if you put the encoded file onto the T/L, how does that look?

Sorry for so many questions, I'm kind of gropping in the dark a bit here. I once (back in V4 days) had to deal with targa files and it looked like I had banding issues however once I encoded the file and played the DVD all looked fine. But also I'm trying to isolate the exact point at which this is happening.

It'd also pay to look at the DV file with scopes, you could be outside NTSC gamut although I doubt that's the problem here.

Bob.

logiquem wrote on 1/17/2006, 6:35 AM

Sorry Fred, this is indeed a very frustrating problem and i have no direct answer for now, but i wonder if some pre dithering could be applied to you images before final mpeg export?

I remember doing this in the past for a cd-rom project. To avoid serious banding on 16 bits displays with 3D generated graphics with heavy gradients , we dithered everyting when importing in Macromedia Director. I wonder if such processing could be made with an image sequence before importing in Vegas?

logiquem wrote on 1/17/2006, 7:14 AM

CineMotion plugin for AE seems to precisely address the banding problem with a "banding reducer" tool...

http://www.digitalproducer.com/2001/12_dec/features/12_03/digitalfilmmakinpt27.htm
http://www.guygraphics.com/frameset-871.html

Hope this help...

fwtep wrote on 1/17/2006, 11:14 AM

farss etc. -- The original frames look fine. The DV AVI from After Effects looks fine. Rending out from Vegas with all of the filters and FX to the Sony YUV codec looks fine. But there's banding when rendering to MPG2 (DVD Arch. settings).

So it doesn't have anything to do with the original frames. And it doesn't seem to have anything to do with the Microsoft DV codec that I'm rendering out from After Effects in. And it doesn't seem to have anything to do with the filters and FX I'm adding in Vegas (Color Correction, Movielooks, etc.).

It's most noticable were the character's cheeks start to get rosy. (But the colors are still legal for NTSC.)

I know that MPG2 is capable of looking great with 3D animation because, for example, the Pixar films sure look great. There must be some setting I need to change.