Vegas RGB output to Window Secondary Display

KinHor wrote on 6/26/2011, 10:28 AM
Hi,

This is my first post.

Just got a HP Dreamcolor monitor to hook-up to my HP EliteBook mobile workstation for colour monitoring.

In order to use the Dreamcolor REC 709 color space, it only takes in progressive RGB input to it's HDMI or Displayport.

Before spending more money to get a i/o box from Aja or....I like know,
is Vegas RGB output to Window secondary display for preview on external monitor accurate for colour monitoring?

Thanks,

Comments

MarkHolmes wrote on 6/26/2011, 12:48 PM
I've looked at that monitor myself and wondered if it would be a good color correction/monitoring solution.

This is a good article covering the Dreamcolor as a monitoring solution, btw:

http://library.creativecow.net/articles/garchow_jeremy/HP_DreamColor_CRT_Replacement.php
farss wrote on 6/26/2011, 3:22 PM
If you look at the Secondary Display setup tab in Vegas then.

a) You can apply de-interlacing. I assume this will be done via the GPU.
b) You can load an ICM profile.
c) You can convert from convert levels to computer RGB.

One thing I'm uncertain about is the risk of applying the same conversion twice, your monitor uses an internal LUT.

Another thing I'd like to know is how to feed a monitor 10 bit RGB from Vegas without the considerable expense of using HD SDI. Actually even with HD SDI, how to setup Vegas to feed 10 bit values to the HD SDI interface card.

Bob.
KinHor wrote on 6/26/2011, 7:08 PM
Thanks for the replies.

On the Secondary Display setup tab I've set to,

a) de-interlace, when timeline is interlace.
b) use color management and apply ICM.
c) use Studio RGB
d) on my nVidia Quadro control panel set to "let application control colors"

nVidia Quadro cards can output 10 bit RGB thru their Displayport. I'm feeding the monitor thru Displayport.

This article says that "Apple YUV>RGB conversion cannot be trusted for color correction. Adobe Premiere’s— version CS5 now handles realtime YUV to RGB colorspace conversion 100% on its own, and that Adobe guarantees the accuracy of this realtime conversion with all transitions and modes that use 32-bit floating-point, which fortunately covers all seven of Premiere CS5’s color correctors!"

http://provideocoalition.com/index.php/atepper/story/does_premiere_cs5_achieve_the_impossible_dream_for_critical_evaluation_moni/P0/

Can anyone from Sony confirms that Vegas YUV> RGB colorspace conversion can be trusted for critical color evaluation?

Kin Hor
musicvid10 wrote on 6/26/2011, 8:26 PM
"Can anyone from Sony confirms that Vegas YUV> RGB colorspace conversion can be trusted for critical color evaluation?"

This is a peer forum, and I'm not from Sony, and you are welcome to download my free grayscale that is optimized for Vegas scopes and draw your own conclusions:

http://dl.dropbox.com/u/20519276/dualgray1.png

As well as the popular Belle-Nuit color charts which are excellent for detecting chroma subsampling conversion errors:

http://www.belle-nuit.com/testchart.html

Not quite sure what your references to Apple and Adobe have to do do with Vegas, it would seem apples vs. oranges vs. bananas . . .

Be sure and post your findings back here so we can all benefit from them!

farss wrote on 6/27/2011, 12:00 AM
"Can anyone from Sony confirms that Vegas YUV> RGB colorspace conversion can be trusted for critical color evaluation?"

As Musicvid rightly points out this is peer support forum and you're fairly unlikely to get any response from SCS here.

Unfortunately to accurately answer your question you need to use more than a computer generated chart. As the notes attached to the Belle-Nuit charts explain different encoding matrixes are used for different "YUV" > RGB conversions. Taking that chart and running it through a pipeline and comparing output to input will tell you if anything is remiss within the pipeline and no errors is a good thing.

The problem is it will not tell you anything about absolute standards because the process is RGB>YUV>RGB and conversion errors can cancel out. The only way to test this is from a known good encoded chart. Then you can go YUV>RGB and check that you get the correct answers i.e. the decode is correct. One usually reliable source of such test patterns would be your camera although you want to make certain you're not applying any picture profiles.
At this juncture I'll have have to own up to ignorance. I'm quite uncertain if Vegas does correctly decode Rec 709 or if it still assumes Rec 601 nor do I know if it can handle Rec 709 to Rec 601 conversions. The differences are so minor they've never troubled me but if you're interested in absolute colour then these are rather vital questions that need to be considered.

Hopefully someone who has tested this can chime in, if not I've made available a very short recording of the ARIB Multiformat Bars from my EX1. As far as I can determine this is Rec 709 with no processing by the camera. The ARIB Multiformat bars specification is available here.

Link to my recording is here http://dl.dropbox.com/u/8841527/Card.zip . This is a bit copy of the EX1 card, just to ensure nothing has been done to it. You will need to unzip this to get to the BPAV folder and locate the mp4 file whicg Vegas will open just fine in Vegas.
Anyone else is also more than welcome to download this and compare the results with the specification.

Bob.
KinHor wrote on 6/27/2011, 12:30 AM
Thanks for the 2 charts.

My findings
1) Dualgray1 chart :
a) 235>255 and 0>16 can't see any differences.
b) Applied Level filter-computer RGB to studio RGB, can see all the white and black bars.

2) Belle-Nuit color HD chart:
Super White and Super Black regions - same as above.

Without Level filter, the image looks brighter/saturated.

KinHor wrote on 6/27/2011, 12:33 AM
Bob,

Thanks for your reply.