CurtPalme.com Home Theater Forum

[benareeno]

can the dvdo units do low end gamma and/or greyscale correction? And if so, is it in a service menu?

[cinema mad]

DVDO's Vps inc flagship VP50pro only have A basic RGB Gamma, Bias & gain for RGB & good selection of internal test patterns
but no CMS.. The Gamma does not offer 11 point and is farly course adjustment..

Lumagen XD/XE on the other hand has it all the complete tool box, CMS, (21 point?) 11 point gray scale and Gamma also has internal test patterns so it can be used as A pattern Gen, thus allowing you to get the best performance out of
the Display device its conected to provided you know what you are doing and put in the time to Calibrate..

Cheers...

[Nashou66]

All the lumagen Vision series have 11 point gamma and the HD series visions also have a limited version of the radiance CMS(no secondary adjustment).

Its also nice beacause you dont have to stick with the pre defined 0ire-10 ire-20 ire etc you can set the gamma to what ever ire's you want to you can use all 11 points for a smooth range from say 0-30 ire at 11 points in that range.

Athanasios

[CIR Engineering]

Lumagen Radiance processors now support 21 point grayscale / gamma correction in addition to all the other features.

craigr

[armstrr]

hey guys...is there a guide or set of instructions that goes over how to properly set gamma with the HDP? I watched lost the other night...and i KNOW i missed a lot of detail in the dark cave scenes...its driving me nuts!

[cinema mad]

To calibrate for Accurate Gamma you realy need A Probe like Chroma 5, i1pro, Color Munki and Calibration software like CalMan..
https://www.curtpalme.com/forum_archived/viewtopic.php@t=19549.html

Cheers...

[kal]

Shameless plug:

Anyone looking for a Radiance video processor (XD, XE, or the new XS) can contact me at kal@curtpalme.com. We offer interesting discounted bundles with other items such as meters (your choice) and CalMAN. For more info see: http://www.curtpalme.com/CalMAN_RadianceXD_kit.shtm

Then there's also the new VideoEq Advanced Colour Processor for a fraction of the price. The VideoEq is for you if you want a complete parametric (multi-point) greyscale/gamma adjustment with a full blown colour management system, but have no need for a scaler or video processing like offered in the Radiance. See: www.curtpalme.com/VideoEq.shtm
We had these on sale for $200 off last month (beyond the CurtPalme.com discount) and we're willing to extend this sale for the next day or two for anyone that missed it!

Kal

[kal]

Shameless plug:

Anyone looking for a Radiance video processor (XD, XE, or the new XS) can contact me at kal@curtpalme.com. We offer interesting discounted bundles with other items such as meters (your choice) and CalMAN. For more info see: http://www.curtpalme.com/CalMAN_RadianceXD_kit.shtm

Then there's also the new VideoEq Advanced Colour Processor for a fraction of the price. The VideoEq is for you if you want a complete parametric (multi-point) greyscale/gamma adjustment with a full blown colour management system, but have no need for a scaler or video processing like offered in the Radiance. See: www.curtpalme.com/VideoEq.shtm
We had these on sale for $200 off last month (beyond the CurtPalme.com discount) and we're willing to extend this sale for the next day or two for anyone that missed it!

Kal

[CRT_Ben]

[kal]

Oops! Forgot the word "off". They were $200 off the regular price (beyond the usual CurtPalme.com discount). At $200 each I would have bought 10.

Kal

[kal]

Oops! Forgot the word "off". They were $200 off the regular price (beyond the usual CurtPalme.com discount). At $200 each I would have bought 10.

Kal

[CIR Engineering]

[armstrr]

[cinema mad]

Your all set then,
Set the Gray scale and Gamma with your Calman by bringing up the aproprete test Patterns using the Lumagen as the
pattern Gen, CalMan has the option to automate this by using the Lumagen RS232 port, then calibrate the Display and Lumagen
to gether, but use the Display's Adjustments as much as possabile Contrast Brightness, RGB Balance, Gain Bias (inc Moome cards Gamma), before using the Lumagen to optimise Gray scale/ Gamma .... Then go onto tweeking your Sourse components...

Depending on you Video chain config, screen and the Room enviroment usualy determend's the optimum Gamma Target, I prefer 2:35
Not 2:2 in my total light controlled theatre...

Follow the complete procedure in CalMan as you need to complete a few steps before Gray scale & Gamma..

Cheers...

[VideoGrabber]

cinema mad commented:
> DVDO's Vps inc flagship VP50pro only have a basic RGB Gamma, Bias & gain for RGB & good selection of internal test patterns, but no CMS. The Gamma does not offer 11 point and is a fairly course adjustment. <

This is correct, as far as the normal User or Service Menu items are concerned. However both the VP50 and Pro have a little known capability for 1024-point gamma adjustment, on each of the 3 primaries. It requires both enabling the point-mode AND loading the LUTs, which can only be done by a PC (or potentially a standalone MCU with enough comm smarts to be able to talk to the VP50's, and 6k of Flash). There is no way (OSD) to adjust these directly on the VP50.

I spent a large amount of time last year trying to pry this information out of DVDO, finally got it (with the help of Dale), and went through and found some protocol details that were incorrect. Since this high-resolution Gamma mapping table is NOT located in NVM, that means it is lost every time the unit is powered down. Re-loading it, over the rather clumsy DVDO protocol, takes roughly 7-8 seconds (at maximum baud-rates), and basically requires you keep a PC attached to the serial port. That pretty much shoots it in the fanny for most people.

I never followed through on this for 3 reasons: I burnt up all my free time just obtaining the tech info; there was a 3rd party who already wrote a basic app framework to allow manipulating these curves, but it was incomplete and NOT talking the proper protocol (DVDO changed it on him). But I got no response to my attempt to contact him.

And lastly, because when I inquired here, the intrinsic limitations (hassle) described above for keeping the data loaded must have scared everyone away, because I got only one or two expressions of interest. That was way too small a payoff for the work that would be involved to put a UI on something like this. Due to the practical issues (and lack of free time), I haven't pursued this, though I may do so at some point in the future for my own use. I've already indicated that I'd post if and when that happened, and it hasn't yet.

When it comes to actually trying to set up gamma curves, having parametric adjustments, as the Lumagen's offer, would likely be easier than direct access to every quantization point on the curve... UNLESS you had software on the PC that provided similar manipulation capabilities, OR could take as input the 3 existing curves from a measurement tool, and automatically generate compensating curves to fit.

Also, the vP50 adjustment process is not incremental in any way. I.e., it's basically a batch mode, where the entire table MUST be reloaded every time. Still, if you happen to have a VP50, I can see, oh, maybe 2 or 3 people worldwide who might want to be able to take advantage of it.

[VideoGrabber]

I wrote:
> ...the entire table MUST be reloaded every time. <

Thinking about it a bit more, I realized that's not quite accurate. Each curve must be cleared and reloaded in one pass, but Red, Green, and Blue could be done independently, which might speed things up for certain tweaking operations. That would cut the adjustment cycle down to ~3 seconds after each adjustment.

If I were to come up with something to give away, it would likely be a simple VP50_GammaLoader utility, that you'd drag & drop a CSV file onto, and it would establish comms with the VP50, load the table, and auto-enable the point mode. Since the data would be in a standard file format, you could load it into various spreadsheets (or another custom tool) to see and manipulate the curves graphically. Then use the Loader utility to dump the modified curves back in.

(BTW, once the curves have been loaded, the UI on the VP50 does allow the user to switch back and forth between the normal "flat" curves, and the custom curves. So you could visually evaluate the results quickly, in A/B comparisions.

Also, I should probably clarify that, AFAIK, simply turning the power off on the VP50 doesn't clear the table in RAM, since the unit still has power internally. I haven't confirmed that, but that's my understanding. But any time there's an interruption in power, outage, shut off at a power-strip, etc. you kiss the LUT in RAM goodbye. That much I am sure of.)

If HCFR (or some other calibration tool) had a way to dump its measured curves to a CSV file, the GLoad tool could also have an auto-compensate mode to convert those readings into correction factors instead, and linearize the net curve. Lastly, given an inflection point and slope, it could auto-gen a low-end gamma compensation curve, parametrically.

I think it's highly unlikely at this point that I'll ever expend the effort to put a fancy graphical UI on something, so users could see, tweak, and load curves interactively. I've got way too many "fun projects" on my to-do lists to devote that kind of time on freebies. Unless, of course, DVDO wanted to pay for the development, which I'm confident they would not.

[cinema mad]

Hi Tim,

Wow thanks for sharing this very useful info .. So Dale does'nt work at DVDO anymore ? I know he left but then came back at one stage(working from Home) He hinted that he had been working on CMS gamma and Gray scale algorithm's while not at DVDO, I know Josh left A fair while ago...

Over on AVS There has been hints from People who claim that DVDO where working on A CMS Gray scale & Gamma solution for the VP50pro..
I think people would be willing to pay to have this needed capability as I have noted on AVS so DVDO get something back for there investment, It would be great if you could make these Adjustment real time Directly through CalMan using the VP50pro's RS232 like the new Video EQ Pro I know its only A Dream..

Cheers...

[VideoGrabber]

cinema mad,

you're welcome. No, Dale left, but may work on various projects from time to time as a contractor. He still has contacts inside though, and he was kind enough to help me obtain the information.

I know nothing about any of the hints of what they may be working on. However, I do know the LUT table capability is there in the hardware, and even though it currently has only a clumsy block-load protocol, and no UI, it doesn't have to be that way. They could provide both an OSD for adjustment, and more refined access commands, if they felt it was worth their time.

Even if there is a fundamental limitation in the hardware, that there is no space for non-volatile storage, you could still have PC commands to pull the data out, once tweaked, and save it for safe-keeping. Along with a re-loader. Saving it externally would also mean you could have as many mappings as you needed.

I even considered an outboard module (with embedded micro) that would plug into the serial port, and when it detected the unit booting up from a cold restart, would wait until the process completed, then send the commands automatically to reload the tables, and enable the custom curves. But a dedicated outboard unit like that would cost hundreds of dollars, and likely have very few customers. It would basically be a band-aid solution.

[HogPilot]

VideoGrabber,

I've been talking with some very knowledgeable people on this subject, and I just wanted to ask a couple clarifying questions. Firstly, the volatile memory that this gamma adjustment feature is located in is separate from the FPGAs correct (I'm assuming the FPGAs are the NVM that you mentioned earlier)? Secondly, is there also a built-in ability to add a full CMS (gamut adjustment) feature as well, or would that be a completely separate endeavor?

From what I understand, the FPGA's on the VP50 and VP50Pro contain all of the code that's hardwired on the ABT2010 chip that drives the Edge and Duo (minus the MNR/Edge Enhancement/Detail Enhancement for the VP50). This is why the FPGA in the Duo has the space for the recently added parametric gamma/greyscale and quasi-CMS whereas the VP50 and the VP50Pro do not. Ironically, with the smaller FPGA on the Duo as compared to the VP50Pro, the Duo may not have the space for a full CMS vs the limited xy for primary only adjustment it has now. Apparently ditching the MNR/EE/DE on the Pro would free up enough space for a full CMS in the FPGAs on the Pro, but the chances of DVDO doing that are about nil. I've also asked how easy it would be to "drop" an ABT2010 chip/card into the VP50 or VP50Pro to free up all of the space in the FPGAs for a full CMS - no answer on that yet. However if it's something that could be done for a total fee of say $500 with CMS firmware fully tested and ready to load (no future promises, we've seen how DVDO has done with those...), I bet there would be a lot of VP50/VP50Pro owners who would go that route happily.

Any thoughts?

[HogPilot]

[ilias]

[ilias]