Brightness of HD Rendered in sRGB vs cRGB?

MH_Stevens wrote on 3/17/2008, 11:35 PM
Vegas 8b HD project shot on XDCAM EX.
Captured files converted with Cineform NEO-DH to .avi
Color space is sRGB
Rendering to HD mpg (using Wolfgang's settings detailed in "HD Highest Quality" thread) to be played as data file on computer with Nero Showtime.

Problem: If I render without converting to cRGB result in Nero is washed out. If I convert to cRGB result in Nero is too dark with all shadow detail lost.

Comments

GlennChan wrote on 3/18/2008, 12:56 AM
1- Presumably you mean "studio RGB", not sRGB.

1b- Either studio or computer RGB is correct. In an 8-bit project, if rendering to Vegas' default MPEG2 encoder (from default Cineform), no conversion should be necessary.
In a 32-bit, you should convert to computer RGB since that's what the MPEG2 codec expects.

2- Are there video overlays affecting the Nero output?

Does Nero apply video "enhancements"?
MH_Stevens wrote on 3/19/2008, 10:25 AM
Glenn: Thanks as always but I still have an issue here. This is a 32bit project converted to avi with NEO-HD from the EX1 SxS cards.

Please forget about why the Nero and WMP looks washed out for now because playing back the render on the HD monitor is not washed out, however I have these two questions.

FIRST when I play the Vegas timeline to the external monitor it looks better than if I render to m2t or m2v (best quality) and play that file on the same monitor. Is that a normal thing?

SECONDLY to have my Vegas preview and my rendered files look good (IE like the camera image) I DO NOT NEED CONVERT TO computer RGB. If I apply a track conversion to computer RGB everything goes very contrasy and dark. This pratical situation seems to contradict what you have said. Can you explain for me a bit more.

Thanks,

Mike
Spot|DSE wrote on 3/19/2008, 11:16 AM
Bear in mind that Nero and WMP are affected by any settings in your overlay/video card. Vegas is not.
MH_Stevens wrote on 3/19/2008, 11:24 AM
Thanks Douglas, and so I ask what about the external monitor? Will that be processed too or is it pure like Vegas preview?

GlennChan wrote on 3/20/2008, 3:27 PM


What compositing gamma are you using? 1.000 compositing gamma will make the computer RGB <--> studio RGB presets not do what they say. So either use 2.222 compositing gamma, or use different numbers, or sandwich the presets with gamma conversions.

2- What are you using as the external monitor?
Windows secondary display?
A HD-SDI card?
Firewire?

They all behave differently, and may not necessarily give you an accurate representation of what your rendered file will look like.

3- I could be wrong about Cineform always decoding to studio RGB. It might be possible to set it up to decode to computer RGB. One way to check would be to capture(?) the same footage both through Vegas and through Cineform and compare.

4- Ok so for a quick recap this is what I would do.
You're in a 32-bit project, so Vegas' MPEG-2 encoder will expect computer RGB levels.

Your source files are Cineform files, which usually decode to studio RGB levels.

Switch your project to 2.222 compositing gamma and apply one of the studio --> computer RGB presets.
And heck, shotgun the other options. No conversion, and computer --> studio RGB.

Render out the three versions.

Play them all back in DVD playing software. (Or burn some actual DVDs.) It should be that the studio-->computer RGB converted render looks right, and the other two progressively more washed out.

-- Ignore the external monitor for now. It can be misleading unless you set it up right.

*This information is specific to your situation.
Wolfgang S. wrote on 3/21/2008, 5:23 AM
"If I render without converting to cRGB result in Nero is washed out."

I am not sure if it is a good idea to use Nero for that at all. The issue could be - I have not measured it - that maybe Nero cuts away super-white and super-black. So, maybe it limits your luminance from 0..255 to 16..235. For super-black that is no issue, typically our camcorders do not record super black. But they record super white.

But as said, I did not check that really.

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Others: Edius NX (Canopus NX)-card in an old XP-System. Edius 4.6 and other systems

craftech wrote on 3/21/2008, 6:17 AM
Although I don't do HD yet I think the problem may lie with the video card and the monitor in terms of 601 vs 709 color space and how they have been calibrated.

John