AVS › AVS Forum › Display Devices › CRT Projectors › A post for Nvidia HTPC users, TSE Gamma curve and CRT projectors
New Posts  All Forums:Forum Nav:

A post for Nvidia HTPC users, TSE Gamma curve and CRT projectors

post #1 of 35
Thread Starter 
Hi Everyone,

I rarely make any useful comments on this forum so here's something I've been playing with tonight that I hope my benefit htpc users out there especially those with Nvidia graphics cards, vmr9 rendering and AC projectors.

Since TSE's gamma curve arrived at our doorsteps I've been trying to do the same thing with the nvidia gamma controls to stop the black crush on my BG808s, made worse by the fact its AC and streaks like a b*tch. Which mainly results in light spilling everywhere My initial experiments in re-creating the TSE curve in the nvidia controls seemed to have no or little effect. My basic procedure was as follows:

1. Put up a full screen video-black pattern (ie RGB 16)
2. Turn down brightness to the point where video-black was absolute black
3. Take a look at the DVE brightness calibration screen, see how bars showed

Even with or without the TSE gamma curve I could only ever very faintly see the brightest of the 3 bars on the DVE test pattern (think off the top of my head its around RGB 25 or so, the remaining 2 are something like RGB 20-22? and the last is less than RGB 16, blacker than black). I could never get that second bar to show against the background, which goes back to the old rule of "With an AC pj you can never have absolute black without crushing"

So why am posting this? After thinking about it for a while an idea came to me, when adjusting the nvida gamma curve, this runs from RGB 0 all the way up to RGB 255, hence the little boost I've been putting in at the bottom has only been increasing the BTB stuff below RGB 16, hence my picture was still crap. Now take a look at this curve:


What I've done here is instead of curving straight up, I've come in a few clicks first, then started the incline at around RGB 16. The results are stunning! I've now got RGB 16 at absolute black (ie no light output from my screen at all) yet I can still see RGB 18, and on the DVE test pattern, I can now see 2 out of the 3 bars

If anyone has an Nvidia card and wants to give it a go, try the following:

1. Set up a modified TSE curve like the one I've shown above
2. Put up an all RGB 16 screen (i've attached one if needed) and adjust brightness till its absolute black
3. Put up a screen with RGB 16 background and some RGB 18 content (again one attached) and see if you can clearly see the 18 above the 16.

If its of any help, I'll post the registry keys of my curve so people can just import them directly in. I'm keen to hear peoples thoughts about this "modified TSE curve" and how they find its works for them, especially if you have an AC pj (the curve might be a little steep for LC as they have less light leakage than my sieve of a Barco .

Hope this is of help to someone,

Jon



I've now attached the registry file for my curve shown above. However you'll need to open up the .reg file in notepad and change the path from "VEN_10DE&DEV_0141........" to your own graphics card's id (just take a look in your registry under "HKEY_CURRENT_USER\\Software\\NVIDIA Corporation\\Global\\NVTweak\\Devices" and you'll see the id for your card there. Once imported it should show up as the "TSE curve v6" on your gamma config (yes I had 5 failed attempts before this one ).

 

RGB Test Patters.zip 55.87890625k . file

 

tse gamma v6.zip 3.3779296875k . file
post #2 of 35
I vote this as sticky!
post #3 of 35
well done!

Gamma has always been an issue with my crt projectors...I'm quite sensitive to it as having it misadjusted really makes the picture worse. I'll give this a shot when I find a new projector!

Ben
post #4 of 35
It IS possible to have a gamma curve that only enhances shadow detail and doesn't effect the rest of the image.

You may have to play with the values for your particular PJ, but here are the numbers I'm currently using.

In FFDSHOW select LEVELS, then CURVE from the dropdown box. Then just select points on the curve and move them until they match these numbers, or whatever values you want. Works great!

0: 16,0
1: 21,35
2: 56,61
3: 142,138
4: 255,255
post #5 of 35
Did not realize that the Nvidia program allowed you a advanced mode like that. Right now without using any gamma correction the gray scale looks correct on the screen. I'm going to mess with it anyways just to see what I can do with the darker details.

Oh, and I almost forgot, that is with perfect black out's.

Deron.
post #6 of 35
Great, VERY helpful post. I've been trying to do what you just did ever since I got my PCI-E video card. Now I don't have to wait for the new Beun box to see how a corrected gamma curve improves the look of my home made HD DVD's.
Please, if its not too much trouble, I'd appreciate the registry file with the points you used.
post #7 of 35
Thread Starter 
OK everyone I've edited the post and added the registry keys so you can import my curve directly to have a play with, just follow the instructions above. Sisyphus good work with ffdshow, especially useful for those who don't use Nvidia. Guess the only drawback to using your method is that you have to have ffdshow in the video chain.

Jon
post #8 of 35
I created a custom color profile for my display with Spyder2Pro Software that gave me dead accurate D65/Gamma down to 5IRE without defocusing blue .
Then I used PStrip to capture the LUT and save it. Unfortunaly, there is no way for NVidia to properly load my LUT so that I can apply Jon changes. My only option is start from default linear ramp
By the way, I also suggest playing with the upper end of the curve. Try to increase gamma values at the top IRE ends by making the curve more steep while keeping the mid low portion unchanged. That will reduce overall luminance and help intra scene contrast. Especially usefull with low Contrast ANSI devices. Try it.
post #9 of 35
For those that know the evil twin had a post about this some time ago.........


ALSO what you have here is a curve for ALL 3 tubes.........

You can actually do one for each RED BLUE GREEN........


the second pull down box - "All channels"........

Gives even greater control.


I am a great fan of Nvidia - apart from one area which I wont mention!
post #10 of 35
Ile posted this on the EVIL TWIN ................

After I tested Tse's gamma correction card, I want to do something similar using GF6600GT videocard drivers.

I was tested normal linear gamma curves before, but I didn't like that washed out look that those make to mid- and upper tones in my pj. Those also have too small correction to low 5-10 IRE's to my taste.

I make custom color correction file in Nvidia drivers. I use scope to see outcome better, because that driver window is so crappy and there is hard to see how correction is working. With stepped testpattern in scope it is much easier to understand.

File can't be exported and I couldn't dig it from XP (I think it's inside several registry), so here is picture of curve if someone want to give a try.

Here is coordinates to all points.
In / Out
0.07 / 0.09
0.09 / 0.14
0.16 / 0.25
0.26 / 0.34
0.37 / 0.41
0.50 / 0.50
0.70 / 0.70
post #11 of 35
Do you know if those point locations can simply be typed into the respective boxes instead of trying to move points with your mouse that are very difficult to get into the right spot.
post #12 of 35
Thanks for this, I'm going to have to try this out.
post #13 of 35
Thread Starter 
Quote:
Originally Posted by none74 View Post

Do you know if those point locations can simply be typed into the respective boxes instead of trying to move points with your mouse that are very difficult to get into the right spot.

lol, its the simplist things that always elude me thanks for the tip!

Oh and for anyone who wants to type my graph in manually here's the numbers:

In/Out
0.05/0.00
0.07/0.09
0.10/0.13
0.15/0.18
1.00/1.00
post #14 of 35
Thread Starter 
Quote:
Originally Posted by MadMrH View Post

Ile posted this on the EVIL TWIN ................

After I tested Tse's gamma correction card, I want to do something similar using GF6600GT videocard drivers.

I was tested normal linear gamma curves before, but I didn't like that washed out look that those make to mid- and upper tones in my pj. Those also have too small correction to low 5-10 IRE's to my taste.

I make custom color correction file in Nvidia drivers. I use scope to see outcome better, because that driver window is so crappy and there is hard to see how correction is working. With stepped testpattern in scope it is much easier to understand.

File can't be exported and I couldn't dig it from XP (I think it's inside several registry), so here is picture of curve if someone want to give a try.

Here is coordinates to all points.
In / Out
0.07 / 0.09
0.09 / 0.14
0.16 / 0.25
0.26 / 0.34
0.37 / 0.41
0.50 / 0.50
0.70 / 0.70

Thanks for reposting the info MadMrH, I've not had a chance to try ILE's graph yet on my pj, but I've stuck in and here's what the graph looks like:



Will report back once i've tried it out.

Jon
post #15 of 35
I've been running a custom curve for awhile now. I probably should've made a post about it. lol. Forgot about using the print screen button to show an example. lol. It works really great. I wish to have this type of gamma control over every non pc source.

Is the TSE gamma correction circuit using the same type of curve that doesn't effect midtones/saturation much? If not, can it be made to have the same type of curve?
post #16 of 35
Yeah just type them straight in..................

I found the curve I posted a little TOO washed out...........

But each PJ will be slightly different.

I would also guess EACH colour should be done seperatly........(Just my current thought)
post #17 of 35
I just tried the curves on my computer crt. Ile's curve was to washed out and Javer's curve did to little on the bottom end. I used the Nokia test pattern to see the changes. I played around with some other curves and noticed that you want to keep anything over .1 in closer to linear. I tried the curve 02 12, 06 15, 09 17, 23 25, 41 41 and it looked better than the other two curves.
post #18 of 35
Quote:
Originally Posted by MTyson View Post

Is the TSE gamma correction circuit using the same type of curve that doesn't effect midtones/saturation much? If not, can it be made to have the same type of curve?

Tse box makes similar effect to non pc sources and in it's possible to adjust amount of boost in most of them.

Box that I scoped effected little more also to midtones and didn't had so drastic boost to 0-5% area. Using digital boost also makes possible not to boost below black area and that mean more useful voltage area for visible shades. That's good thing, least in theory...
post #19 of 35
Hi There,

Anyone with an Nvidia card and powerstrip ?

Colour profiles/configure/capture and you can save out the registry key


Or http://www.gretagmacbeth.com/product...photostudio_sw

Download PM 5 Photostudio's calibration tester...It has the capability of viewing/Loading/Saving luts

and curiously http://www.avsforum.com/avs-vb/showthread.php?t=777353

A video equaliser, which can also load/save things, though there is no visual output apart from the screen change !

Anyway....i have an ATI card and as such also wanna play !

Ta,
Lee
post #20 of 35
I`m using PowerDVD 7.3, and it seems that it uses overlay. In the Nvidia color profile window I`m allowed to choose overlay and modify the curve, but it doesn`t do anything to the video? If I use eg. Zoomplayer and choose desktop I see the changes I make to the curve affect the video.

Does this only work with VMR?

Gunnar
post #21 of 35
Quote:
Originally Posted by Gunnar View Post

I`m using PowerDVD 7.3, and it seems that it uses overlay. In the Nvidia color profile window I`m allowed to choose overlay and modify the curve, but it doesn`t do anything to the video? If I use eg. Zoomplayer and choose desktop I see the changes I make to the curve affect the video.

Does this only work with VMR?

Gunnar

Last night when I was playing around with this, I was choosing "ALL" from the drop down menu (not just desktop or overlay).

It was affecting PDVD 7.3.

(But of course it was affecting overlay too.)
post #22 of 35
Ok guys,
I have played around with this gamma thing in nVidia drivers for the last 2 nights and it seems to me that I may have a malfunctioning driver/card.

The problem is that it works only sometimes.
Let me explain:

Sometimes when I am modifying the curve, I see a difference. At other times I don't!
Why?

The same thing happens with all:

* Power DVD 7.3
* Win DVD 8 Platinum
* Windows media player
* MCE

When I modify the curve, I select all from the drop down menu (instead of overlay or desktop)

I have a nVidia Quadro FX550 AGP card. The drivers are the latest version:

ForceWare Release 90
Version: 91.85
Release Date: April 13, 2007
WHQL Certified



By the way since my DVE DVD is gone missing I am using the star wars DVD's THX optimizer test (the one which has the THX with BTB drop shadow).
post #23 of 35
Tried "All", but still doesn`t work in PowerDVD 7.3. I`m using driver version 93.71 and the card is a PCIe 7800GTX. Works in "Desktop" mode. Another strange issue is that suddenly there is a lot of red streaking from black objects in the picture. I see this with both overlay and desktop when showing video. If I raise the brightness to say 108% it is not visible. Grr... i hate this HTPC thing..

Gunnar
post #24 of 35
Tried the same with my other PC, which has a 6600GT videocard and older drivers. Same result, no custom colorprofile works with overlay and Powerdvd. BUT if I turn off H/W-acceleration in Powerdvd it seem to use VMR! Then I can chose "All", and apply a custom colorprofile. I have a Core2Duo PC, so hopefully I don`t need the H/W-accel.

Gunnar
post #25 of 35
I tried som more with PDVD 7.3 on my HTPC today, and it behaves differently from my office PC which have PDVD OEM 6.5. The former seem to use overlay even if H/W-accel is turned off, so no luck so far with the HTPC. If I leave all controls at default the image is very dark. I have to raise the brightness control to about 108% to get about the same brighness as from the HD-DVD player.

Gunnar
post #26 of 35
Now when I saw this thread again, I remembered that last month I saw one of my friend and he told me that he was coded something similar custom gamma adjustment program for Ati+Powerstrip combo. It was already working and he got points from my curve transferred to register. Program was still out of GUI and independent rgb curves, not sure about current status of that project...
post #27 of 35
I'm making slow progress thanks to my hectic work schedule but it's getting there. I started writing this program since I wanted to be able to control gamma in a same way that Nvidia drivers do but was stuck with my ATi card.

I can already draw very nice custom curves with the software and save them in a format that powerstrip can work with. I have a basic GUI up and running which shows the gamma curve and In & Out coordinates for every point. There's no limitations as to how many points you can have the gamma curve to go through and you can freely move, add and delete them. Curve is always calculated as a smooth curve passing through every point. Currently I can choose the resolution for the curve as I like and it automatically scales it to 256bit before saving. 1024bit format is also possible, but as far as I know Powerstrip only supports 256bit gamma curves. I might be wrong so please be free to correct me if this isn't so.

First task on my ever growing To-Do list is to finish the GUI in order to make the program more usable so that also people other than me can make a good use of it. After the GUI is done I'll start working on independent RGB curves. As it is now you can only adjust all colors at the same time. There's still some thinking to be done on how to do this, but it's a feature that I WANT so it will be there eventually.

Future features that I've been thinking of is saving the gamma curve directly to the windows register and I'd also like to be able to adjust the gamma curve in realtime. But since I'm writing this program on my free time (which is fairly limited at the moment) this all takes time.

If any of you have any wishes or ideas please don't hesitate to contact me. I'll do my best to incorporate them to the software once I have cleared the top priority tasks from my To-Do list. For example if you'd like to be able to save custom gamma curves in a different format other than what's supported by Powerstrip...

- TNR
post #28 of 35
Thread Starter 
Sounds good TNR, I expect there's a lot of AIT users eagerly awaiting this software!

Jon
post #29 of 35
Hi TNR,

Any beta testers wanted .... Even if its a basic fudge, if its useable i'd like to play !

Ta,
Lee
post #30 of 35
Quote:
Originally Posted by Alaric View Post

Hi TNR,

Any beta testers wanted .... Even if its a basic fudge, if its useable i'd like to play !

Ta,
Lee

You'll get to play with it for sure, don't worry. As do everyone else who's interested. I just want to finish the GUI so that I'm comfident enough of letting it out of my hands. After that I'll start working on the independent RGB adjustments.

Let's see if I can attach a screenshot to this post... A small sneak peek. I took it yesterday so it's the current state of the program. There's a box for the curve and a textarea that contains some basic info: Mouse cursor location, pass-through coordinates and all In/Out coordinates of the curve.

- Tero
LL
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: CRT Projectors
AVS › AVS Forum › Display Devices › CRT Projectors › A post for Nvidia HTPC users, TSE Gamma curve and CRT projectors