CurtPalme.com Home Theater Forum

[hansilili]

Dear all,

neither am I willing to compromise for too low phospor usage nor do I want to accept a greenish frame around my d65 calibrated picture. Based on the ideas of "balancing CRT wear using a negative burn mask" (seems too risky for me) and "blending with a PC and pixelshader" I got the idea to uses a pixel shader, custom made to balance my green tube mask. A pixel shader is a little programm which runs on the GPU and transforms all video frames according to the programmed routine. Several software players allow easy selection of pixelshaders, I use dvbviewer pro and media player classic. The idea is to overlay a negative of the visible section of a mask resulting in a uniform grey scale of the projected picture.

Searching the web for tutorials about pixel shader programming gave some results. The code is written in a language called HLSL, which is supposed to work very much like C++. Unfortunately I have never read or written any type of code. Being stuck with my idea I would need the help of a more experience programmer.

I think it would be ideal to have a generic code, which would multiply the original color of a pixel with the one of the same pixel in a static grafic file. The individual grafic file would be a color adjusted negative of a photograh of the projected mask on the screen. Understood?

If incorporation of a photo does not work in HLSL, then one would have to describe the mask using geometrical funtions.

Please all you programmers out there let me know if I could at least make clear where this should lead and how it could work. If you think it helps you can PM me and I will further explain on the phone.

Best regards
HAns

[hansilili]

No comments at all?

[Ile]

I'd try to find better green tube, that gives also more light output.

[antorsae]

Hans,

I just got my projector working again and I'll continue to improve my PC blending program. My next step in the blending program is to do fullscreen color correction in addition to blending; to have PERFECT color uniformity without the need of Marquee's CCM board. I believe this is what you are looking for.

Since I do this on my spare time, development slow; so bare with me....

-Andres

[hansilili]

Hola Andres,

exactly that is it what I am looking for. I have been following your work on the blend shader and this really was sthe starting point for my idea in the first place.

Correct me if I am wrong, but is it really so complicated to overlay (superimpose) a transparent graphic file on the image? If a pixel shader is not the right way then may be there are other ways to appy a custom filter. Would this be possible using AVIsynth? Could someone who is familiar with AviSynth please check http://avisynth.org/mediawiki/Overlayand comment if it is could be a way? Again, for to dig into this matter is like learning chinese.

Thanks
HAns