Sky Q UHD only working in 8 bit output

[FredMel]

Hi all,

First post. Sky Q box installed in 2023 and linked to Samsung 55" S95C (which accepts 10 bit). However watching Sky or TNT uhd sports output only yields an acceptable picture if the Sky Q output is switched to 8 bit, despite the box recognising the tv as 10 bit. In 10 bit mode the picture is unacceptably dark, but with occasional bright highlights. Have checked cable (HDMI 2.1), TV settings, etc. Anyone else experienced this or can offer a solution?

[Quoman7]

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@FredMel wrote:

Hi all,

First post. Sky Q box installed in 2023 and linked to Samsung 55" S95C (which accepts 10 bit). However watching Sky or TNT uhd sports output only yields an acceptable picture if the Sky Q output is switched to 8 bit, despite the box recognising the tv as 10 bit. In 10 bit mode the picture is unacceptably dark, but with occasional bright highlights. Have checked cable (HDMI 2.1), TV settings, etc. Anyone else experienced this or can offer a solution?

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Hi @FredMel have you checked the HDMI input setting on your TV is set to "enhanced" ?

[nigea99]

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@FredMel wrote:

Hi all,

First post. Sky Q box installed in 2023 and linked to Samsung 55" S95C (which accepts 10 bit). However watching Sky or TNT uhd sports output only yields an acceptable picture if the Sky Q output is switched to 8 bit, despite the box recognising the tv as 10 bit. In 10 bit mode the picture is unacceptably dark, but with occasional bright highlights. Have checked cable (HDMI 2.1), TV settings, etc. Anyone else experienced this or can offer a solution?

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hi @FredMel 

In 10 bit mode you will be getting UHD/HDR.

On SKY Q they use a form of this called HLG (Hybrid Log Gamma)  which requires a Peak Brightness of the Panel to be  higher than other versions of HDR - typically at least 600 cd/m2 (aka Nits) although  some may get away with as low as 500 but anything below that & customers will almost certainly feel it unacceptably dark

I am guessing your TV will be one with a lower peak brightness & thus you find it too dark.

Although you may not find it , you could try doing a google search for your specific TV model & Peak brightness todouble check your TVs capability

As you have found, our suggestion for this is to use in UHD/SDR mode by setting to 8 bit

[FredMel]

Thanks for the quick response but peak brightness of the Samsung is reported to be 1200 nits, so there should be plenty of headroom.

[Quoman7]

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@FredMel wrote:

Thanks for the quick response but peak brightness of the Samsung is reported to be 1200 nits, so there should be plenty of headroom.

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@FredMel Make sure Contrast Enhancer is turned off
Contrast Enhancer is a function that automatically adjusts your TV's brightness so that the difference between bright and dark areas is not excessive. When this feature is turned on, your screen may automatically appear brighter or darker. 

[nigea99]

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@FredMel wrote:

Thanks for the quick response but peak brightness of the Samsung is reported to be 1200 nits, so there should be plenty of headroom.

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hmmm - in which case I admit I am puzzled

THe darkening effect with HLG/HDR will affect the image but should definitely not cause such a screen to be unacceptable - my TV has aorund 700nits

I shoud say that some customers do notice the darkening if they normally use the very artificially  bright modes oftenb called Vivid, dynamic & some sports modes. As these often use a brightness near the maxiumum , when the dimming  occurs , as I say, customers used to these bright modes do notice but it should not be unacceptable.

[FredMel]

Thanks for the suggestion, contrast enhancer was on low but switching off had no effect.

[FredMel]

I have, it's called input plus on the Samsung & is enabled.

[FredMel]

The problem does appear to be confined to Sky Q HLG content. Streaming Disney, Netflix, etc. in UHD/HDR doesn't yield any problems.

[lettice]

Have seen the Samsung S95C recently running Sky Sports F1 and Sky PL, both in HDR on Sky Q.

The picture, I must admit was fine and would not say dark. 

Are you running it in filmmaker mode, that is the best mode to use for Sky Q HDR, I recall.
Also, make sure you have the motion smoothing option turned off.

[FredMel]

Tried everything you suggested (thank you) but to no avail. The only thing that made a difference was increasing the HLG setting in the Samsung menu from 0 to 3, but the picture was still very unsatisfactory.

[FredMel]

Ok, have now obtained an acceptable picture after some tweaking with the following settings:

picture mode: standard

brightness: 50

contrast: 50

sharpness: 10

colour: 25

tint: 0

picture clarity: off

contrast enhancer: low

hdr tone mapping: active

colour tone: standard

white balance: 2 point

gamma: hlg

.hlg: 3

shadow detail: 0

peak brightness: high

will try a little more tweaking but this, at least, yields a useable picture (note high HLG setting).

[Chodley]

Gamma not have an Auto setting? I would imagine you don't want that on HLG when you play SDR or HDR10 stuff through the Q

On most TVs when using HDR the brightness and contrast are both 100 (assuming the scale is 1-100) but I can imagine on a 1200nit screen that makes any larger bright areas pretty full-on nuclear, and it's only bearable with specular highlights. Did you have to turn it down or is that what the samsung defaulted to? Or is 50 the max maybe?

(and as an aside I don't know why Brightness gets maxed out on HDR since it's supposed to set the level of the dark parts of the image, but that's what seems to happen and it works ok on my OLED TVs)

[FredMel]

The gamma settings only apply to HLG (the tv auto detects this) & max brightness on the Samsung is indeed 50.