Levels question

[iSeries]

Hi all, quick question. If MadVR and GPU are both set to output full RGB, but the TV is expecting and working in limited, what would be the expected result when displaying a black clipping pattern?

[Cary Knoop]

If you monitor/TV expects video levels you should not expand the levels on your PC to full.

[iSeries]

Thanks, but just looking for an answer to the question. At the moment I do not know whether the TV wants full or limited.

[Cary Knoop]

Display an ARIB SMPTE bar.
If you see the pluge (which is at sub-black level) you send video levels to a full range monitor/tv.
If you do not see the two lighter black bars you send full levels to a video levels monitor/tv.


If you do not see the pluge and you can see the two lighter black bars your levels are ok.

https://upload.wikimedia.org/wikipedia/commons/thumb/6/60/SMPTE_Color_Bars_16x9.svg/1024px-SMPTE_Color_Bars_16x9.svg.png

[pirlouy]

From what I understand, if your TV can handle Full RGB in input (depending on the brand, you should have a setting for that), test pattern will look the same as if you output limited RGB (with "limited" input in your TV setting).

Maybe your question was to know if your TV is working internally in Full or limited RGB ? I'm sure Huhn knows this, but I'd say that if you're not in "PC/monitor mode", expect algorithm not in 4:4:4 RGB.

[iSeries]

Thanks guys, the TV itself doesn't have an option to switch between limited and full. I do believe it to be full though.

[Asmodian]

If you send a display full when is expects limited it will clip everything below 16 to 16 and everything above 235 to 235 (displays 16-235 as 0-100% brightness). This means clipping in shadows and highlights.

I like the AVS HD 709 test patterns from AVS Forum (https://www.avsforum.com/forum/139-display-calibration/948496-avs-hd-709-blu-ray-mp4-calibration.html) but the ARIB SMPTE bar pattern works too.

[iSeries]

If i send full rgb, bar 17 barely flashes, as does 234. However, if i send limited, same thing. So i don't know. The tv is set to 'auto' colour space, so maybe it is able to tell the difference and adjust accordingly

[huhn]

auto is a "thing" and some TV detect PCs and use a special PC mode fully automatic i heard TCL does this.

for testing i just use this RGB image and no player.
http://www.lagom.nl/lcd-test/black.php

it's simple.
if your GPU is set to full range and you see all squares you are golden.
if the TV expects limited >a lot< of levels will be crushed.

[Asmodian]

Understanding how to test with madVR is a little tricky but always leave the GPU on FULL when testing.

Set madVR to limited, if you can see bars below 16 your display is in full, if not it is in limited.
Set madVR to full, if your display is limited you should not see any bars flash.

[iSeries]

Thanks guys, it's full.

"Set madVR to limited, if you can see bars below 16 your display is in full, if not it is in limited." - if I do this, all bars flash. Switch MadVR back to full, only 17 (barely) and up flash.

for testing i just use this RGB image and no player.
http://www.lagom.nl/lcd-test/black.php

Thanks for the link Huhn, this also confirms that when the TV receives RGB, it is working in Full (Vizio P65-E1) - I see all the squares.

[Warner306]

Vizio should have an option called "Color Space" that can be set to RGB or YCbCr. At least, the new ones do.

Edit: I looked up your display on Rtings.com and it appears to have this setting. RGB should be full and YCbCr, limited.

[iSeries]

The RGB setting is completely broken. The only option that works is Auto, and it passes the tests above, so all good

[Asmodian]

"Set madVR to limited, if you can see bars below 16 your display is in full, if not it is in limited." - if I do this, all bars flash. Switch MadVR back to full, only 17 (barely) and up flash.

Very nice! That is a perfect black level, it is always nice to be able to see 17 but it should only be barely visible. :)

[iSeries]

Yeah i'm shocked how good it is out of the box!The 'calibrated dark' preset is spot on. I might not even have to get the meter out...who am i kidding, i'm definitely going to get the meter out lol.

Thanks all again.

[huhn]

vizio likes to cheapout on HDMI port try a different port.

you may need to actived UHD deep color or something like that to make HDMI 2.0 bandwidth available

if the e1 is the 2017 e series you have to do follow this:
Most of the common input resolutions are supported, except 120 Hz. 4k @ 60 Hz @ 4:4:4 or 4:2:2 color is only supported on HDMI input 1, and only when 'HDMI Chroma Subsampling' is enabled. 4:4:4 color is only displayed properly in the 'Computer' picture mode.

source is rtings.

[iSeries]

Hi huhn, it's the 2017 P series, ports 1-4 support all the same stuff, with port 1 additionally supporting ARC. 'UHD Full colour' is enabled.

https://www.rtings.com/tv/reviews/vizio/p-series-xled-2017

I do need to switch to 'computer' mode to enable 4:4:4, however, that defaults the TV to it's native 'wide' gamut, with no way to change it, That'll be perfect for when I create a 3dlut for it, but for right now I'll have to slum it with 4:2:2 til I rack up some hours on it ;-)

All good.