Samsung tv gies darker on UHD

[kdwilk]

When I switch my tv to an UHD channel the tv picture goes darker 

[SlenderRobert]

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@kdwilk wrote:

When I switch my tv to an UHD channel the tv picture goes darker 

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If the UHD content has HDR (which a lot of sports content does) then you'll need to tweak the picture settings on your TV to adapt for the HLG format of HDR which Sky uses. If your TV does not have a particularly high brightness level then UHD with HDR will produce a darker image. 

[MightyQuinn]

Hi @kdwilk   Change your Sky Q Picture Resolution to 2160p 8 bit which will change the picture to SDR. With 10 bit it is trying to output HDR and it appears that your TV is either not suitable or needs setting for HDR.

[Chodley]

What model TV is it? Do you know what its peak light output is?

[crumby]

what is the difference from 10 bit to 8 bit and why should it matter just asking cos i changed it in my settings and way better..

[Chodley]

10bit, which is required for HDR, means there are 2 to the power of 10=1024 possible values for each of the Red, Green and Blue values in the image information for each pixel. That gives a total of 1024x1024x1024=approx 1billion possible colours for every dot (not that every TV is capable of displaying all of them properly)

8bit, same maths, can only represent 256 x 256 x 256 = 16million colours. Which is what SDR uses.

The reason why HLG specifically, which is only one way of handling HDR, looks dimmer on some TVs is that it has to work seamlessly on TVs which can only display SDR. So a TV which is very good/bright at HDR (about 800nits or more) will show bright highlights clearly very bright and normal stuff will look normal.

A TV that can't go that bright, but is attempting to display HDR will show "highlights" as normal brightness and what should be normal will be relatively dim.

So switching to 8bit stops it attempting to show the highlights as "different/more bright" and shifts all the rest of the colours back to their usual level of brightness and the overall picture looks better.

Basically if your TV can't do in the region of at least 600-800nits it will probably be bad at HLG.

HDR10 (used by the streaming apps) doesn't have the same problem because it is not intended to work on SDR screens so the overall brightness curve does not get pushed down in the same way.

[crumby]

mine definitely does have 10 bit and im sure the sky q does and it only seems on different channels time after time say with footie for example im wondering does your have this problem to  especially when you put it onto hdr mode of course if you wstch footie 

[Eeeps]

There's a great explanation from the BBC (inventor of HLG) as to why it can look dim on a HDR display.

Dim HLG display

Basically, in HLG the normal SDR peak white is set two stops lower than the peak brightness of the HDR display.

This is to allow very high brightness parts of the picture (e.g. floodlights, the sun etc) to appear much brighter and show the benefit of the HDR display over a SDR display.

This means that even a display that can do 1000nits will only output 250nits for a normal peak white.

[Chodley]

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@crumby wrote:

mine definitely does have 10 bit and im sure the sky q does and it only seems on different channels time after time say with footie for example im wondering does your have this problem to  especially when you put it onto hdr mode of course if you wstch footie 

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I'm not sure you read my post properly (or I wrote it badly). Having 10bit/HDR support is not enough. The TV also needs high enough peak brightness (600-800nits or more) for HLG to work well.

[Chodley]

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@Eeeps wrote:

There's a great explanation from the BBC (inventor of HLG) as to why it can look dim on a HDR display.

Dim HLG display

Basically, in HLG the normal SDR peak white is set two stops lower than the peak brightness of the HDR display.

This is to allow very high brightness parts of the picture (e.g. floodlights, the sun etc) to appear much brighter and show the benefit of the HDR display over a SDR display.

This means that even a display that can do 1000nits will only output 250nits for a normal peak white.

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Exactly

[Jimach]

I had the same problem and found that the cause was the bandwidth of the TV was not sufficient to handle the extra UHD data. The solution which worked for my TV was to open the iPlayer app, go to settings, then video quality and turn off the best quality setting. Hope this works for you.

[Chodley]

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@Jimach wrote:

I had the same problem and found that the cause was the bandwidth of the TV was not sufficient to handle the extra UHD data. The solution which worked for my TV was to open the iPlayer app, go to settings, then video quality and turn off the best quality setting. Hope this works for you.

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That probably disabled HDR

[crumby]

so is that even with say like sky q then which seems to be always the problems especially say football always goes darker

[Chodley]

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@crumby wrote:

so is that even with say like sky q then which seems to be always the problems especially say football always goes darker

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Who is that question directed at? Forum doesn't show who you replied to unless you quote them with the " button