Discussions

[VTHokie96]

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botan1982 wrote:

In my case, on the 55p605 TV, problems with HDR arose precisely after the 9.2.6 update on October 20, a computer and ps 4 were connected to the TV, problems were observed both here and there, but in the TV application YouTube HDR works correctly. It is simple to check the incorrect operation of the firmware - you need to return the previous firmware, but no one wants to help me with this.

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If your problem with HDR is screen darkening, RokuTanner has been helping others with TCL "P" series with same issue on a different discussion on this forum.  I believe he's been helping some of those earlier on with this issue with firmware downgrades but more recently others had upgraded with latest firmware which corrected the problem.  Search "TCL 55P605 since Roku 9.1 HDR dark" on this forum.

[botan1982]

I wrote in that topic(TCL 55P605 since Roku 9.1 HDR dark), but did not receive help.

[Sjims]

After 9.2 The same with PS4 but only if I choose tv inputs name as a computer, if i choose PlayStation, game console, xbox, or my own name everything is fine. Tv 55s515

[VTHokie96]

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@Sjims wrote:
After 9.2 The same with PS4 but only if I choose tv inputs name as a computer, if i choose PlayStation, game console, xbox, or my own name everything is fine. Tv 55s515

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Sjims, I tried what you did.  Switched input to my 55R615 TV (from my HTPC) from Custom Name to Computer, to Bluray, to Game Console back to Custom Name, trying each choice while swapping back/forth between HDMI 2.0 & Auto Modes for each with no success.  HDR still darkened.

[VTHokie96]

FYI

I had been PM'ng RokuTanner who informed me that he has directed this issue to the development team.  Since this HDR darkening issue appeared on TCL "P" series TV's on v9.0 (or v9.1) and was corrected with v9.2, I'm hoping TCL "R" and "S" series issues noted here on v9.2 will soon be corrected. 

[botan1982]

I confirm that after changing the input instead of “computer” - “console”, HDR worked on the computer and on PS 4 when I changed “computer” to “playstation”.

[ssft]

Ok so I've got an interesting observation here after seeing the comments about changing the input to Computer mode.

The TV is able to automatically detect that a PC signal is being sent and puts the TV to PC mode.  You can also force PC mode by changing the input name to 'Computer'.  So my Apple TV has been working just fine in HDR even after the update.  However... if I change the Apple TV's input label to Computer and set Apple TV to output HDR10, the extremely dark/dim problem now shows up with Apple TV.  Setting it to Dolby Vision does not show any issues.

So it sounds like the problem here is specifically with PC Mode and HDR.  Unfortunately since the TV auto detects this, there isn't a way to force PC mode off when using a PC.

[VTHokie96]

Tried to confirm but none of the methods (switch inputs, naming,..) improves my 55R615 issue.  HDR always dark.  I was on 9.2.0 build 4120-30 but was updated to build 4129-30 by RokuTanner as a test to see if any improvement.  Unfortunately no change.  I'm back on build 4120-30.  Neither build offer a solution for me.  Hopefully developers are on top of this an correction is offer soon.

[ssft]

I have a workaround!  Because the TV is forcing PC mode (and where I believe the HDR problem seems to be), I found a way to stop this behavior and have the TV accept the PC signal in "non PC-mode".  Once I did this, voila Windows now has beautiful bright HDR.

1.  Open Nvidia Control Panel

2.  Go to "Adjust desktop color settings"

3.  Change the "Content type reported to the display" from auto-select to "Full screen videos".

4.  Ensure the input label on the TV is anything except Computer.

5.  Test HDR from Windows, it should now be bright and working as it should.

The downside to this is that now the TV is not in PC mode, which means there is a bit more latency and also text may appear fuzzy because it isn't doing 4:4:4 chroma subsampling.  So this still needs to be fixed, but at least we are further in getting back HDR on PC.

Additional info from a rtings.com blog regarding another TCL model, but which gave me the idea to try and "fake" the signal so the TV wouldn't think it's a PC:

Update 07/18/2017: The TV only shows 4:4:4 color properly when in 'PC mode'. Sharpness also has no effect in PC mode, even though the slider can still be changed. For most sources PC mode is activated by changing the input's icon to 'Computer'. For a PC, if the TV detects a PC as its source it forces PC mode, and this cannot be avoided except by intercepting the AVI infoframes sent from the PC. Changing the input's icon does not avoid this forced PC mode. This behavior was not known during initial testing, leading to the incorrect assumption that 4:4:4 color is displayed properly in all modes.

[VTHokie96]

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@ssft wrote:

I have a workaround!  Because the TV is forcing PC mode (and where I believe the HDR problem seems to be), I found a way to stop this behavior and have the TV accept the PC signal in "non PC-mode".  Once I did this, voila Windows now has beautiful bright HDR.

1.  Open Nvidia Control Panel

2.  Go to "Adjust desktop color settings"

3.  Change the "Content type reported to the display" from auto-select to "Full screen videos".

4.  Ensure the input label on the TV is anything except Computer.

5.  Test HDR from Windows, it should now be bright and working as it should.

The downside to this is that now the TV is not in PC mode, which means there is a bit more latency and also text may appear fuzzy because it isn't doing 4:4:4 chroma subsampling.  So this still needs to be fixed, but at least we are further in getting back HDR on PC.

Additional info from a rtings.com blog regarding another TCL model, but which gave me the idea to try and "fake" the signal so the TV wouldn't think it's a PC:

Update 07/18/2017: The TV only shows 4:4:4 color properly when in 'PC mode'. Sharpness also has no effect in PC mode, even though the slider can still be changed. For most sources PC mode is activated by changing the input's icon to 'Computer'. For a PC, if the TV detects a PC as its source it forces PC mode, and this cannot be avoided except by intercepting the AVI infoframes sent from the PC. Changing the input's icon does not avoid this forced PC mode. This behavior was not known during initial testing, leading to the incorrect assumption that 4:4:4 color is displayed properly in all modes.

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Tried your workaround which resulted in a slightly-less darkened HDR display screen but still not at full brightness for me.  Text wasn't crisp either.  I'm using 4:2:2 @ 60Hz.  Same result at 4:4:4 @ 30Hz