MPEG2 Color issues

VicViper wrote on 10/30/2008, 9:44 AM
I have a Quicktime file of animation and whenever I render it into MPEG2 (with the intention of being put on DVD), the colors, especially darker browns, look too saturated or off.

No matter what I play with in the color correction settings, it doesn't seem to make a difference once it renders into MPEG2. Prior to render, it always looks normal.

I looked at some of the specific color values before rendering (or even attempting at correction), and they're within the RGB 16-235 range as well.

Any advice on how to correct this would be appreciated.

Thanks.

Comments

rs170a wrote on 10/30/2008, 11:23 AM
If this animation is a series of still frames, odds are that it's coming to you in 4:4:4 (uncompressed) or, at the very least, 4:2:2 (mildly compressed) colour.
When you render to MPEG-2, this gets changed to 4:2:0.
Look at this page on Adam Wilt's site for an example of what this transformation does.
What this means is that your colur information takes a real beating and I don't think there's a good way to avoid this.
I stand to be corrected though so, if someone knows how to avoid this, please speak up.

Mike
GlennChan wrote on 10/30/2008, 1:51 PM
Check that you're handling the color space conversions correctly. You may need to manually change them yourself to get them right.
http://www.glennchan.info/articles/vegas/v8color/v8color.htm

2- 4:2:0 artifacts are pretty subtle. It's probably not the problem. See this article:

http://www.hometheaterhifi.com/volume_8_2/dvd-benchmark-special-report-chroma-bug-4-2001.html

*the artifacts may be difficult to see on a CRT computer monitor.
VicViper wrote on 10/31/2008, 1:21 PM
Thanks for the response guys.

I got an ok looking, but somewhat washed-out looking correction last night. The best I was able to get so far.

It's clean, but the colors are a bit subdued when you watch on NTSC set via DVD.

But when watching the same DVD on PC, it looks really faded, and the colors are a mess.

I know any studio DVD I purchase typically looks good on either my SDTV or PC. Is there any way to balance the colors so they look really good in both?

Also GlennChan, thanks for sharing the links. I've been wondering though, does working in 8-bit vs 32-bit affect the picture quality? I've been working in 8-bit.

For instance you say in 8-bit, MPEG 2 wants to see/decodes to studio RGB, but in 32-bit MPEG2 wants to see/decode to Computer RGB. I'm not anywhere near an expert on this stuff, but would 32-bit really improve the color and/or picture quality?

I'm guessing it probably won't since MPEG 2 can only display Studio RGB, unless I'm wrong.
musicvid10 wrote on 10/31/2008, 3:33 PM
You didn't mention what compression / bitrate settings you were using in your MPEG2 encode. This is one very important factor. For instance, there is a major and obvious difference in color rendition between 4Mbs and 8Mbs.
VicViper wrote on 10/31/2008, 4:04 PM
I set it at CBR of 8 MB. No Audio either (separate stream).
GlennChan wrote on 10/31/2008, 6:50 PM
Also GlennChan, thanks for sharing the links. I've been wondering though, does working in 8-bit vs 32-bit affect the picture quality? I've been working in 8-bit.
Not really, unless you are dealing with things like glows and cross dissolves. The linear light article on my site explains the most visible differences.

Are you using Vegas' mpeg2 encoder? It sounds like you should be getting the correct levels.
Wander Machado wrote on 10/31/2008, 7:09 PM
I'm having a problem to use mpeg and avi extension.
How can I solve it?
Wander Machado wrote on 10/31/2008, 7:12 PM
When I try to use both extension the information below happen and I didn't get it.

"Stream attribute could not be determined"

Please, I really need to use both extension. Today I just get use the .wmv
GlennChan wrote on 10/31/2008, 7:47 PM
Wander, you should start a new thread with your problem and you'll be able to get more helpful replies that way.