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Full Version: Question about correctly setting Limited Range with a Beamer
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Hi

i have a small home cinema , and i just bought a new Beamer. Since this time i wanted to calibrate my Beamer on my own , i started calibrating. Quite fast i noticed that something is way off. When looking at my calbrated data , i saw that basically the contrast and brightness are way off. After looking around i found out that must be a Kodi Setting.

I already had set the Limited Range Setting in the Settings, but that doesn't seem to be enough , specifically since i have an Intel NUC (there seem to be issues there)

So after some reading , i found out that i need some other tweaks.

My question now , is that what i am doing is correct and that i understood it correctly.

1. Beamer must be Set to Standard (Limited Range)
2. I have to add to Kodi the following setting in an autostart.sh script : xrandr --output HDMI1 --set "Broadcast RGB" "Full"
3. Set the option Limited Range to enabled in the Settings
4. Enable VAAPI

is that all ? is that correct ? or am i missing something ?

It still seems to me after calibrating that not everything is 100% as it should.

thanks for any help.


Fixed with:
- Kodi v17
- Custom kernel with Passthrough Color Mode
Hi. Vaapi doesn't work with the limited range setting in Kodi, that is coming in Kodi 17.
Based on other peoples experiences, Milhouse's latest EGL build of Openelec wiith Kodi 17 alpha seems to work pretty ok regarding show stopping bugs.

If you want to stay on stable, the best would to be is to use software decoding for the test patterns. Afterwards adjust your beamer to full, and also Kodi internal setting to full. That way you will get the least banding, and should work ok until Kodi 17 stable lands in half a year or so..
ok , so i turn off the Limited Range in the Settings,

How about xrandr ? do i leave that on automatic or do i switch that to Full ?

Why Software if i may ask ?
this also means when doing the clipping test that i should see from 0 to 255 ? and also beyond 16 in the blacks ?
Xrandr full in all cases. Software decoding with kodi limited will give the right levels regarding btb and wtw. Which you'll lose when you're going full, full, full after calibration.
ok, if i go full in every aspect.

and if i want to calibrate than my beamer, do i still do a REC709 Calibration or a REC2020 ?
REC709. There's going to be a while before Kodi will output be able to output nondithered 10bit with HDR meta, and even now there's no standard as how to calibrate towards a larger gamut/HDR. If will require HDMI 2.0a, new GFX driver, new code in Kodi, new code in assosicated libraries, HEVC files (althought it could be implemented with 8bit h264, it isn't likely) And not least a compatible a display/beamer. Come again in 2018.. if we're lucky ;D
one last question. If i do full everywhere , do i set to Sofware as well ? or do i remain on Auto ?
No full everywhere is after calibration, when you enable Vaapi. If your NUC is powerful enough and you don't mind fan noise, then by all means use software decoding and use Xrandr full, kodi limited and beamer limited. If you want to use Vaapi, then full everywhere will give you the best quality until Kodi 17 lands, which will enable vaapi to replicate software decoding.
ok , thanks
I tried several options.

One thing i notices if i set the Beamer to Full , xrandr to Full and Kodi also full with Dithering 8 bits on , PLUS Software decoding, i get completely reddish colours on movies.

If i set the Software Decoding back to Auto , Colours are back to normal .

Is that a bug or some other setting i need to do ?
Quote:One thing i notices if i set the Beamer to Full , xrandr to Full and Kodi also full with Dithering 8 bits on , PLUS Software decoding, i get completely reddish colours on movies.

Every version that has Dithering integrated has perfect colors with VAAPI. No need to use sw decoding. As you seem to run a v17 alpha, just keep VAAPI enabled, keep Prefer VAAPI Render enabled and all will be fine.

Quote:If i set the Software Decoding back to Auto
That will bypass all shaders we have (IF you set that to OFF).
So in summary :

If you are running a build with VAAPI + EGL interoperation (and you should be on Intel for the best video output) and you want Limited range for your projector (aka beamer) then :

GPU drivers FULL (aka xrandr Broadcast RGB Full)
Kodi option to enable Limited output (which is a menu option in Kodi settings, though you may need to enable Expert or Advanced to see it)
Enable VAAPI hardware acceleration for MPEG2/H264/VC-1 (*)
Enable Prefer VAAPI rendering

This tells the GPU to output 0-255 levels and it expects 0-255 levels. Kodi with the Limited option set, does a slightly hacky-cheat and sends the VPU 16-235 content (but with <16 BTB and >235 WTW content intact and with no 16-235->0-255 remapping which can cause banding), which the GPU then outputs as 16-235 (with <16 and >235 content intact).

This is a great solution BUT you need to be aware that modern TVs (and I guess projector/beamers) may not perfectly work with this. This is because the GPU drivers will embed an HDMI infoframe (a bit of data in the HDMI signal) that signals that the video content is 0-255. If your display follows infoframes (as newer TVs will - as it is how you route 0-255 and 16-235 content untouched through an AVR) it will switch the display input from Limited range to Full range, and thus will expect 0-255 content (as the GPU has told it it is in 0-255 range) and you will get grey blacks, dim whites and washed out colours. In many cases you can force your TV to ignore info frames for levels and force Limited Range still - but it is something to be aware of. My c.2008 Sony 40W4000 ignores info frames, but my c.2015 Sony UHD set follows them. I suspect as we move closer to Rec 2020, UHD etc. Info frame support will become more widespread, as presumably that will also be used to flag UHD and non-UHD content and 709 vs 2020 colour space as well as 0-255/16-235 level space?

(*) Interlaced VC-1 won't play in VAAPI acceleration (but I think should still render in VAAPI?)
(2016-01-08, 14:49)noggin Wrote: [ -> ]So in summary :

If you are running a build with VAAPI + EGL interoperation (and you should be on Intel for the best video output) and you want Limited range for your projector (aka beamer) then :

GPU drivers FULL (aka xrandr Broadcast RGB Full)
Kodi option to enable Limited output (which is a menu option in Kodi settings, though you may need to enable Expert or Advanced to see it)
Enable VAAPI hardware acceleration for MPEG2/H264/VC-1 (*)
Enable Prefer VAAPI rendering

This tells the GPU to output 0-255 levels and it expects 0-255 levels. Kodi with the Limited option set, does a slightly hacky-cheat and sends the VPU 16-235 content (but with <16 BTB and >235 WTW content intact and with no 16-235->0-255 remapping which can cause banding), which the GPU then outputs as 16-235 (with <16 and >235 content intact).

This is a great solution BUT you need to be aware that modern TVs (and I guess projector/beamers) may not perfectly work with this. This is because the GPU drivers will embed an HDMI infoframe (a bit of data in the HDMI signal) that signals that the video content is 0-255. If your display follows infoframes (as newer TVs will - as it is how you route 0-255 and 16-235 content untouched through an AVR) it will switch the display input from Limited range to Full range, and thus will expect 0-255 content (as the GPU has told it it is in 0-255 range) and you will get grey blacks, dim whites and washed out colours. In many cases you can force your TV to ignore info frames for levels and force Limited Range still - but it is something to be aware of. My c.2008 Sony 40W4000 ignores info frames, but my c.2015 Sony UHD set follows them. I suspect as we move closer to Rec 2020, UHD etc. Info frame support will become more widespread, as presumably that will also be used to flag UHD and non-UHD content and 709 vs 2020 colour space as well as 0-255/16-235 level space?

(*) Interlaced VC-1 won't play in VAAPI acceleration (but I think should still render in VAAPI?)

Therefore I implemented kernel Video Range 16:235 which signals Limited Range info frame and does not clamp: http://fritsch.fruehberger.net/kernel/
But , is it better now (if one has a Beamer in my case JVC x5000) to put it on Full, Full, Full or Full, limited, limited ?
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