Contrast - video texture

i’m searching for a way to edit the contrast of a video texture.
the contrast pin on the videoTexture node doesn’t seem to work on my graphic card. i tried a spread of the video texture, but on high CPU usage the spreads don’t play synchronized.
is there a way to control the contrast without implementing pixel shaders, or how can i implement pixel shaders in vvvv.



i think its possible to use a freeframe video filter to change the contrast.

read this tiki pages for more information:

HowTo Freeframe for video filters
Effects Network for shaders


the contrast pin on the videoTexture node doesn’t seem to work on my
graphic card.

yes, we also failed to see a card, where this is supported. i guess this is a driver issue with very low priority for graphic card vendors.

The freeframe solution sounds plausible, but pixel shaders is the recommended way though. Use a shader with a color transform matrix pin. This pin allows you to do arbitrary matrix transforms on the rgba components of the video. With this technique you can change brightness, contrast, saturation, hue-shift, color-tint of your video in realtime just by applying a transformation to the color matrix. Matrices can be concatenated just like normal 3d-transforms for placing 3d objects and textures. even chroma-key etc. should be possible.

drawing the same quad over and over again (by means of a spread, e.g. just spread the color pin of your quad) can be a quick workaround, but you likely exhaust the pixel fill rate of the graphic card if you draw a huge number of full screen quads.

concerning the pins on the videotexture…the way they don’t work partly is my fault. so here is the whole story:

as you may have noticed there are currently two versions of the videotexturenode shipping. only the one that is supposed to do deinterlacing also is supposed to have the color transformation pins working. this is due to a fact how directx internally works with videotextures.

the problem is that the deinterlacing version happened to be very buggy as soon as you want to do some more graphics than just playing back a video on a quad. but you may want to try that for yourself. if you have one of the more recent ati or nvidia cards with their latest drivers some of the pins should work if you choose the deinterlacing videotexture.

anyway i’ll give the videotexture a rework soon since microsoft said it fixed this bug in xp sp2 with directx9c.

thanks, i think freeframe was the tool i was searching for but my
v4 b8.1 crash after a few seconds if i load a freeframe dll.
i tried a simple patch with filestream, countour.dll (or other dll’s from their website), videotexture, quad, renderer.
i use the most recent drivers (04/2004) for my old ATI mobility Radeon 7500 on a winXP SP2.

is this a common problem?