Color banding on the 5k+


#1

This is a subject that I haven’t seen discussed much. How much of a problem is it? What’s the cause? Limitation of the hardware? Performance saving in the lower quality settings?


#2

Thanks for creating this thread. Here are questions I have posed elsewhere without any response.


#3

The forgotten issue. Here are two examples of it. All questions in my post above are still relevant.

SweViver at 2:34:37

mixedrealityTV at - 1:01:05

Sorry, both set at the time stamps now.


#4

Color banding of the 5k+ is another reason for me to continue to prefer the 8k, in addition to black level and brightness (not to be confused with color temperature). Thanks for the thread and for updating again. So far there has been too much monothematic talk about sharpness.


#5

It shouldn’t be possible for the hardware to produce color banding unless it’s not a true color (24 bit) display. The human eye can perceive up to 10 million colors, while 18 bit displays tops out at 262,144 colors.

18-bit
Almost all of the least expensive LCDs (such as typical twisted nematic types) provide 18-bit color (64 × 64 × 64 = 262,144 combinations) to achieve faster color transition times, and use either dithering or frame rate control to approximate 24-bit-per-pixel true color,[9] or throw away 6 bits of color information entirely. More expensive LCDs (typically IPS) can display 24-bit or greater color depth.

It’s possible that the color spots on the 5K+ are a result of dithering on a 18 bit display, and the color banding would also be an artifact of that. If this is the case I doubt the 8K panel is a 24 bit panel, I think the color gradients and dithering are more blended on the 8K due to the blurring effect from upscaling.


#6

I can see banding in the mirrored output so it might be input related. My rift definitely shows banding in certain games so I’m not too concerned just yet


#7

Bingo. The smaller dots in a 45 degree pattern, combined with the error diffusion to correct for the missing subpixels, cause a dithering effect that dissolves gradient banding. The 5K+ in this case has successfully reproduced a rendering weakness. This is why it’s been recommended to add a slight bit of noise to VR rendering (if that’s done in the lens warping pass, there will be more banding on the desktop mirror that recordings are from than in the headset). The banding is also likely to be exaggerated on video, and this may be a difference between Valve and Pimax compositors. HDR would be a very good thing for VR, something I hope to see once we have compression enabled.


#9

@mixedrealityTV
@SweViver
@VoodooDE

Could one of you have a quick look if there is colorbanding in the 5k+ in EliteDangerous or in a test image stronger than in the 8k?

That would help me and maybe others to decide which headset to choose.

Thanks in advance.

edit:
sorry only now seen the linked video from sweviver. Since no one else is interested in this problem (except the few in this thread), pimax will probably not fix it.

I will therefore stay with the 8k.


#10

Would like some more info on this, I got my decision email a couple days ago from Pimax but have not responded yet because I’ve been hoping for some more information from other backers who hopefully get their units soon…


#11

@mixedrealityTV has said that Pimax will/may be able to address the colour in the 5k+

http://forum.pimaxvr.com/t/friendly-advice-with-sugar-on-top-do-not-go-for-the-8k


#12

He was talking about color balance and contrast, I think, not banding.