601/709 vs. RGB

[Jiri Bakala]

I admit, it's confusing. Here is my question:

If the workflow requires going from HDV to DVD SD, what should be the colour space. I am working in native HDV 720p30 in Avid XP and need to export to DVD SD. By now I have tried some 20+ variants. It basically boils down to the following:

-export to uncompressed QT using either 601/709 or RGB colours
-import resulting QT into iDVD and burn

As it seems, no matter what I do I am getting washed out colours and raised blacks. Exporting in RGB actually seems to be slightly better than sticking to 601/709, although not quite as rich as when the same footage is played from the HD50 (mastered back to HDV). I guess that might be the result of the DVD MPEG2 compression?

Which also brings me to another issue; I am viewing the material from a DVD player using component AND composit outputs to a 21" HD LCD (native 1280x720, Sony). The component signal seems less saturated and less contrasty, while the composit albeit not as sharp (of course) presents more pleasing colours and contrast.

Anyone stumbled upon a good 'white paper' workflow for Avid? I am not getting anywhere on the Avid board either.

[Steven Thomas]

Originally Posted by Jiri Bakala

As it seems, no matter what I do I am getting washed out colours and raised blacks. Exporting in RGB actually seems to be slightly better than sticking to 601/709, although not quite as rich as when the same footage is played from the HD50 (mastered back to HDV). I guess that might be the result of the DVD MPEG2 compression?

Which also brings me to another issue; I am viewing the material from a DVD player using component AND composite outputs to a 21" HD LCD (native 1280x720, Sony). The component signal seems less saturated and less contrasty, while the composit albeit not as sharp (of course) presents more pleasing colours and contrast.

Jiri,

This may sound like a crazy question, but have you tried a "store bought" DVD
using the same setup you tried with your test DVD? I'm just wondering if your 21" HD LCD levels are set correct for the analog inputs?

My HD set has DVI and analog inputs (like most :)). The levels are totally different between these inputs. I have to have seperate monitor settings or the luminance levels are incorrect.

It sounds like your making the correct settings.

You probably already know this, but I'll hash over a bit on levels. I made some references to Sony Vegas, since it's what I use.

NTSC (601) RGB - black level is 16 16 16 RGB, and white level is 235 235 235 RGB. This is the same for DVD. Sony Vegas calls this "studio RGB"

Computer RGB white level should be at 255 255 255 RGB. Black level should be at 0 0 0 RGB. Sony Vegas calls this "computer RGB". Vegas has a level filter setting to go from computer RGB to Studio RGB. This allows you to use your NLE (Computer RGB) to make level adjustments. Then when you're finished, you can convert to NTSC. In your case for DVD.

It's easy to see the importance of using a calibrated monitor as a real time preview from your NLE. If you're optimizing your levels while viewing your computer's RGB monitor, remember black is 0. If you have your blacks concentrated below NTSC black level 16, the blacks will look crushed on a NTSC monitor. Although, they will look correct on your computer monitor.

Now, I see you're exporting correctly to 601 preparing for DVD.
BUT, it may be possible that when iDVD converts your uncompressed to MPEG-2 DVD format, it also does the 601 conversion.

If this is the case, I'm not sure of the result, but it might explain why your DVD video looks "washed" out. You may want to try just going uncompressed without any conversion and then use iDVD to make your NTSC DVD.

Woops... I just reread your thread. You did try exporting without the 601 conversion.....hmmm.
Have you had good luck before using iDVD? Has anyone? I don't know, I have never tried it.

You may want to try a different MPEG-2 encoder. I have seen great differences in quality.
I've been using Procoder 2.0 which looks good.

Steve

[Jiri Bakala]

Thanks Steven,

I am using a SONY HD 21" 16x9 monitor with DVI and analogue inputs and there is a huge difference between the inputs, particularly between component and composite. The composite is much more saturated and contrasty while the component and DVI are very close to each other and somewhat "washed out" by comparison. I did try a few commercial DVDs (Baraka, Powaqquatsi among others) and they look right on the component/DVI side - so I adjusted the composit input to match as closely as possible.

Since my last post I tried a few more variants of the HDV -> DVD SD workflow and the following seems to yield best results:
-export from Avid (HDV 720p30) as QuickTime 864x486, uncompressed, current size, best quality and millions+ colours - in RGB colour profile (you do have to choose one or the other)
-import resulting file to iDVD and burn

I would be still interested in some sort of 'white paper' that explains the colour space considerations for HD/SD and DVD, as well as the computer vs. TV. If someone has a link or a saved file?

Thanks.