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post #331 of 332 Old 08-07-2017, 10:07 AM
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Originally Posted by FreMo View Post
This is weird because (as already said and sorry to insist) with direct player connection into the display, when I set the Oppo's output to 4:2:2 12 bit I see "deep color 36 bits" on the information label of the tv.

When the same signal goes through the Radiance before entering into the TV the "deep color 36 bits" label is not displayed anymore, like if the signal was 8 bit.

Could this be a cable problem? Because I tested separately both of them in direct connection configuration between player and TV and all worked fine.
Not a cable problem.

The Radiance and Radiance Pro 4:2:2 output is ALWAYS 12-bit. The 4:2:2 output mode was an original HDMI mode and not added as part of "Deep Color." So it does not have, or need, a "bit depth" VIC code. If the player is sending a VIC code for 4:2:2 "bit depth" it is going beyond the spec.

So it does not in the least matter what the TV reports for 4:2:2. If you have the Radiance Pro output set to 4:2:2 it is 12-bits. If the TV followed the HDMI specification correctly it would report 4:2:2 as 12-bits since in the HDMI specification 4:2:2 is 12-bits, and no VIC code should be needed for the TV to know this. If there is a failing here it is that the TV software is not correctly interpreting the HDMI spec for 4:2:2.

Note: HDMI does not require that all 12-bits of any deep color mode contain useful data. This is independent of any reported bit depth. Some devices may only have 8 or 10 significant bits in any 12-bit format. However, for the Radiance and Radiance Pro all 12 bits are significant.
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post #332 of 332 Old 10-05-2017, 11:25 PM
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Banding from Lumagen CMS settings

I'm creating 3D LUTS for my Lumagen 2143 / JVC X30. Lumagen is configured for 422 in / 422 out.

I'm struggling with quite a lot of banding in the blue channel, particularly visible in the RGB ramps in the Spears and Munsil 2nd edition disc. The banding is in the form of repeating mini-ramps over the length of a blue channel ramp from 0,0,0 to 0,0,255 - it looks like some kind of mathematical artifact. They're quite distinct.

I've worked out so far that there are two sources of banding:
1) Having Darbee enabled. Not a problem, disable it. (this actually causes banding in all the ramps)
2) Having the CMS do any addition of green to the blue primary position.
I proved this by taking the CMS setting down from 17x17x17 to 8 point, which kept the same primary / secondary locations. The blue primary is then (64,270,920), which is what I measure as being necessary to have blue in the right position. This has the same banding - so the banding is not an artefact from the LUT itself. Changing the value of the blue primary down to (64,64,920) removes the banding.

As I say, this looks like some kind of maths-type artefact. Has anyone else seen this? Is this a settings issue or inherent to the CMS implementation? Thanks!
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