Use SmartShader to reduce ghosting on PVA panels?

[Bas]

I have a suggestion to improve the performance of TFT monitors using the capabilities of ATI's SmartShader.

Many owners, like myself, of PVA based TFT monitors will be annoyed by the slow gray-to-gray response time (>100 ms) in 3D games. However, the white-to-black (and reverse) response of these panels is <25 ms. This feature can be used to enhance the g-t-g response:

A very simple routine should amplify color changes for each pixel, shortening the response time between frames. In the next frame, the "normal" color value should be output to the screen. The adjustable constant needs to be tuned to prevent a color "overshoot".

Based on the SmartShader function in the ATI control panel I suggest the following routine:
1) Take the difference between the currently and previously rendered frame, for the individual values for red, green and blue for each pixel.
2) Multiply these difference values by an adjustable constant (say 0-255). Clip values if outside valid color range.
3) Take values for r, g, and b channel of current frame, and add the values of step (2), for each pixel. Output to the screen buffer.

Note that in order to work, the framerate must be fixed (vsync enabled). When the framerate drops below this value, the constant may be lowered automatically, to compensate.

I hope there is somebody out here to pick up this idea. It should be possible using ATI's PSS plugin, but that only works in OpenGL. Thanks.....

 

[Guden Oden]

I've been wishing for someone to come up with an idea like this, but it wouldn't help me since most games I play are D3D-based, and I have a Nvidia card in my box... Still, it's a cool and useful idea.

 

[Zaphod]

nVidia was touting a feature such as this when they launched the Go 6x00 series. Can't find anything worthwhile about it at their site, though.

Notebook LCD displays can exhibit “ghostingâ€￾ effects because of the slow response time of liquid crystals. The LCD overdrive feature compensate for this slower response time by overdriving color signals, thereby automatically eliminating ghosting effects.

 

[bloodbob]

By that PR description sounds dangerous and sounds like it would only work on analog feeds.

 

[Zaphod]

By that PR description sounds dangerous and sounds like it would only work on analog feeds.

I was under the impression that notebook displays had all been digital for ages. Making it analog would only be more costly, and there's no installed base that has to be catered to thereby not having to add the legacy analog outputs. When I first read it I thought it sounded like something similar to what the original poster is suggesting. Namely making use of the fact that certain LCD panel tech is much faster at high contrast color changes. Given nVidia's affinity for 'digital vibrance' and suchlike it'd make sense that they'd try to pass this off as a good thing by displaying an image that, while technically less accurate, might subjectively look better.

Found an image from their PureVideo PR:

 

[bloodbob]

Ahh yes it appears your right those skys should be the same colour in theory. You could always try my digital viberance smart shader.

 

[db]

most laptops already support this. it's called lcd overdrive.

 

[Zaphod]

most laptops already support this. it's called lcd overdrive.

Most?! I hardly believe so. Linky? Some perhaps. It's not been much more than a year since the first press releases started to appear touting programmable LCD controller ICs with this feature, and to be accurate they'll need calibration to each panel (make and model) used in the system. In the mobile space, where margins are squeezed and weight + power consumption reign supreme over performance, I just can't see either ODMs or OEMs stomaching this cost knowing how many different panels from different manufacturers some (most?) of them usually qualify for a series. At least not without advertising it as a feature, witch they're not. I've seen some of the (panel) manufacturers do for the higher end desktop targeted stuff, though, and I see now that ATI have also listed this as a feature of the Mobility X600 as well, but as of now I'd guess that this feature is more of a paper tiger in most camps. I have no doubt that this may be changing, though, as both GPU and panel manufacturers toy with solutions to keep performance up and cost down while catering to new parts of the ever expanding notebook market.

Or did you mean 'most' as in 'most currently shipping'? I'd be happy to be proven wrong about that as there's been well over half a year since I had cause to go digging through spare parts specs for ODM notebooks and their associated LCD panel specs.

 

[Bas]

Thanks for the feedback so far. I suggested to use ATI's smartshader because it allows to manipulate the image before it's output to the screen (and because I have an ATI card ). I'm sure NVIDIA has similar options to do the trick.

I just wondered if someone would try to program a smartshader preset for this, as my own programming experience stops at Pascal and Matlab

@ Bloodbob: How can I run your "Digital Vibrance" smartshader, and does it work in Direct3D?

 

[bloodbob]

It will only work in OpenGl its not what you asked by but the looks of those screenshots post by Zaphod there digital viberance going on in those images.

http://www.users.on.net/~mccann/DV.pss
http://www.beyond3d.com/downloads/smartshader/pssControl2.zip
put the DV.pss file somewhere extract the exe out of the zip file run the exe and then load the pss file.

If you wanna tweak the strength check here
http://www.beyond3d.com/forum/showthread.php?t=20191