[x86][Intel][xrandr] Wrongly detected RGB Range

marhycz · April 21, 2017 at 1:55 PM

Hi, It's my first bug report, so I hope I write here everything necessary

I am using LE 8.0.1 on an Apollo Lake board (J4205-ITX). So Intel HD 505 GPU.
I have a Panasonic TX-50CS630E TV and I recently bought a LG SH7 Soundbar.

If I plug HDMI or DVI->HDMI output on the board directly into the TV, the RGB range is set correctly.
(I can use either Full RGB settings on TV, or use Normal RGB settings on TV and set 16-235 range in Kodi output settings.)

However, if I use the soundbar (I plug PC output into the Soundbar HDMI input and then Soundbar HDMI out into TV) the RGB range is messed up. In order to have right colors, I need to use Full RGB settings on my TV and 16-235 output in Kodi, which seems to me completely weird.
Normal combinations like Full RGB on TV and Full in Kodi settings or Normal RGB on TV and 16-235 in Kodi settings always produce wrong colors.

I can temporarily fix that by issuing

Code

xrandr --output HDMI2 --set "Broadcast RGB" "Limited 16:235"

through SSH. Then I can set TV RGB range on Normal and keep Kodi 16-235 output settings.

So the problem is, that the system somehow messes up the RGB output, that a combination Full RGB on TV and 16-235 on Kodi is needed.

The full debug log is here:
I started the system, logged in through SSH, issued the command above to correct the settings and exported the log.
EWMJ

The dmesg output is here:
J4205 and LG SH7 Soundbar - Pastebin.com

**DaVu** · April 21, 2017 at 3:07 PM Official Post

Quote from marhycz

If I plug HDMI or DVI->HDMI output on the board directly into the TV, the RGB range is set correctly.

Quote from marhycz

However, if I use the soundbar (I plug PC output into the Soundbar HDMI input and then Soundbar HDMI out into TV) the RGB range is messed

From what I read, it's the soundbar which is causing the issue if the connection: HTPC->TV is fine.

So, tbh, if a device messes something up, then I would blame the device and probably contact the manufactor of that device as I would guess that's not LibreELECs problem.

Normally the soundbar shouldn't touch the video signal in general. If it does, then the soundbar does something wrong and I would drop that thing. If my AVR would touch the video signal in that way, I would call the vendor ASAP.

marhycz · April 21, 2017 at 7:01 PM

Ok then, I thought, that the devices are somehow aware of each other and send some info about them that PC detects. (That's why I can see the name of my TV and Soundbar in Video, Audio output settings for example.)

M3Rocket · May 3, 2017 at 5:17 AM

Quote from marhycz
...
I can temporarily fix that by issuing
Code
xrandr --output HDMI2 --set "Broadcast RGB" "Limited 16:235"
through SSH. Then I can set TV RGB range on Normal and keep Kodi 16-235 output settings.

You can actually just put that xrandr command into configfiles/autostart.sh and have it automatically executed upon boot up.