Dear friend, I have a amlogic d905 box. Until one week ago, I was running a libreelec installation with kodi 17, to be exact the kszaq 8.2.3.1 .
All was ok, but I need kodi 18 for some application like amazon vod, so I installed a coreelec build.
All is working, But I noticed that video output on my projector have a lot of contrast.
My guess is that this is a video level problem ( 0-255 or 16-235) but I’m unable to find in the menu the way to change it (is possible on windows for example).
I connected my box in SSH and tried the command “dmesg | grep RGB” I see:
[ 17.508305@0] hdmitx: video: Bit depth: 8-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
[ 17.858317@0] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
[ 288.768703@0] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
[ 289.179898@2] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
So, It seems to be limited, but I not understand: if I set it “full” (and I don’t know how) I’m afraid of having a worse result. Or not?
Anyway I can try, but how change this setting?
Thanks for your help.
The kszaq kernel and the kernel in our releases is the same both run with limited RGB range.
In fact, I thought so, and yet it is clear that compared to before, I have crunched blacks and clipped whites.
In the meantime I tried to connect a box with windows10 and with that you can change this setting, and the right one is limited.
Previously, when I had the version with libreelec I had calibrated the projector. Now I have recalibrated it to get a correct result but I had to raise the brightness and lower the contrast. It would not be a problem but now when I connect other devices such as the bluray player I see everything washed out.
Anyway, is possible to try change this setting, and how?
Thanks for your support.
An update: I verified by changing the HDMI setting between limited and full (which is called VIDEO and PC) on the projector and I found, using test signals to check the clipping of black and white which despite what seems to be the output of my box is FULL and not LIMITED. How it is possible I don’t know, I ask you for help to verify this matter, because before the change of build it was LIMITED for sure.
My work is Color Correttings and grading, so I’m pretty sure .what I’m seeing.
My question is how I can check at low level this setting, and If I can try to change it.
Sorry I don’t understand half of what your saying.
You can NOT change from limited to full, the kernel just does not have support for it, either in LE or CE.
I think your barking up the wrong tree and need to look at the internal Kodi brightness setting instead.
Sorry if I’m not clear. I cannot change from limited to full because kernel don’t have support. Ok, I understood.
BUT… the problem is that before change from libreelec to coreelec KODI output was for sure limited, Now output FOR SURE in FULL. I don’t know why.
You suggest that I used a wrong tree and I must look to internal KODI brightness.
OK, But how? I cannot found way to do this. Please help me. And, in any case, the problem is not only brightness but contrast also, because I have clipping on black but also on white. As happen when you use a video FULL level with a limited display.
About wrong tree, my box is a Amlogic s900 kII, I used gxbb_p200_k2_pro. I have also my old tree from libreelec, I can try to use it, what do you think?
Anyway, what I’m sure now is that my box, despite support or not, output in FULL mode.
Please enter dispinfo via SSH and paste the provided link.
This is the dispinfo result:
http://ix.io/2h39
Despite seems to be LIMITED, I’m sure that output is FULL
Maybe. Anyway, some other info (I’m trying on a key in order not destroy my installation):
at command
dmesg | grep RGB
I receive this info:
[ 20.941131@0] hdmitx: video: Bit depth: 8-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
[ 21.341142@1] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
After the command (I found it in this forum about odroid)
echo “rgb,10bit” > /sys/class/amhdmitx/amhdmitx0/attr
dmsg change in
[ 20.941131@0] hdmitx: video: Bit depth: 8-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
[ 21.341142@1] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: YUV444
[ 150.271463@2] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: RGB
[ 167.301138@0] hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: RGB
And… Output now is CORRECT. (limited)!!
The problem is that if I restart, the output back to FULL.
I will do some other test in order to have all info.
PS: I have a lot of video test for check this problem, if you need plese let me know, I can share it.
Your still getting confused, your RGB range is still limited NOT full, our kernel simply does not support it.
Your projector is misinterpreting the video mode because of the colour space and colour depth that is being sent.
You can add
echo "rgb,10bit" > /sys/class/amhdmitx/amhdmitx0/attr
to /storage/.config/autostart.sh and your system will always boot into RGB then.
Ok, this is a solution for now, Many thanks.
But I have some questions just to understand.
My projectort does not automatically detect video mode full or limited. For this setting I have a menu item.
About color space, You wrote that RGB is still limited (and yes, it is) because kernel don’t support Full.
What is not clear to me is why in YUV444 color space, I see image as it is full. If I change on Projector menu manually from limited to full, images are ok: Semme that YUV444 is FULL but rgb is limited.
And last, why in my old libreelec installation with same kernel all was ok? Maybe was in RGB color space?
We use auto cs/cd switching in CE that is not used in LE and that is probably why you are only now just seeing this issue.
I think the default in LE is 422,8bit but don’t quote me on that.
Many thanks to all, I solved the problem using RGB color space instead YUVV444.
it remains to understand why yuvv444 output in full mode (in my box). If it were a problem of projector misinterpretation, I would have to see a limited video in full mode instead the opposite happens…
This solution proyector or TV box?
Tengo x96 905x3 air p3 same problem no fix…
Thank