PDA

View Full Version : Banding problem in Volumetric light(help!)



kim_beta
05-05-2003, 04:05 AM
Hi All,

I'm creating an intro for a Showreel to be outputted on DVD (assembled in DVD Studio Pro 1.5). Now, I have a volumetric light. I got a quicktime movie as a projection image (to create feeling of moving light), I got a intensity falloff. the volumetric light is set to Best quality. When I render I get these banding in the darker areas? When I encode this in Bitvice (Mpeg2 Encoder) The banding looks very bad. Is there anyway to output in better quality in LW? Maybe set the render to 10 bit or something? Any help appreciated.

Thanks...

/Kim

eblu
05-05-2003, 10:33 AM
gradients + mpeg = banding.
its a rule. but...
gradients + mpeg + NTSC/PAL = slightly less banding.

your volumetric light, creates a beautiful gradient of color and luminosity, and it becomes a banded mess when compressed. this is what happens, its going to happen, you can't stop it. You can lessen it. you can plan around the problem by keeping the contrast in the gradient low, by only compressing the image once for output (different compressors will band in different parts in the gradient arc... multiplying the problems), and you can rely on the free anti-ailiasing in the NTSC/PAL spec. The less new/ cutting edge the presentation technology, the more free antialiasing you get. On VHS you might never see the banding. On DVD you could try buying an apex player, or perhaps connect the device with RCA jacks instead of S-Video. "test", and "tweak" are the code words for this operation.

Its a sick and twisted problem, and the best solution is to Not use gradients (ie: things that appear as gradients in your render; for example: volumetric lights), but you are probably going to be balancing evils in your situation. try changing the camera angle, try lowering the contrast in the bulk of the gradient.

good luck

kim_beta
05-05-2003, 11:10 AM
thanks for the info, now I only have to choose whether to walk on fire or ash... ;)


Best
Kim Petersen