help needed : S912 box and rgb output on old Philips/Sony Tv's

samgarcia · September 29, 2017 at 4:07 PM

hi,

I tried asking this question in the s912 thread.

I am running libreelec 8.1.9 version on s912 h96+ box. and I have old Philips TV.

on versions before 8.0.2.e you could force the rgb output with this command

#!/bin/sh echo 1 > /sys/class/amhdmitx/amhdmitx0/output_rgb

however the newer version of libreelec doesn't support this configuration via autostart.sh file.

if I downgrade to 8.0.2x and execute this command I loose audio via hdmi.

I have read here something about configuring 8bits/10bits display to force rgb.

I was wondering if someone here could help me with this issue. I would like to keep up with the updates of libreelec, but I am too beginner to know what and where to configure, so my TV screen does not randomly go green/pinkish when I am in the middle of watching a movie.

I asked this question in s912 thread too, but only received short replies and no workarounds. hence why I am asking it here.

please provide me with some guidance how to fix this problem. thank you

**kszaq** · September 29, 2017 at 5:54 PM

Unless your TV provides a way to switch colorspace, there is no way to fix this issue in 8.1.x.

samgarcia · September 29, 2017 at 5:57 PM

what features name or/ specifications should I be looking for to find out if the TV offers colorspace or not.

thank you for your quick reply

**kszaq** · September 29, 2017 at 6:20 PM

Perhaps an option to switch between RGB/YPbPr or Full/Limited Colour Range.

**kszaq** · October 7, 2017 at 10:43 PM

Can you try running this command: echo cs0 > /sys/class/amhdmitx/amhdmitx0/debug

samgarcia · October 8, 2017 at 1:48 AM

Quote from kszaq

Can you try running this command: echo cs0 > /sys/class/amhdmitx/amhdmitx0/debug

nothing happens unfortunately.

I tried it when the screen was green/pinkish

and when the output was RGB

edit: updated to the latest version. still no changes

**kszaq** · October 8, 2017 at 9:00 AM

Try using this command before playing a video, e.g. add it to autostart.sh

**mmpp** · October 8, 2017 at 9:53 AM

Tried it on S905X. Removed all the other settings from autostart, entered the new, rebooted and played a video. Screen turned pink after a few minutes. Nothing in the dmesg after the change to pink.

FXeF

iskonje · October 9, 2017 at 11:19 PM

I have the same problem with my Panasonic Plasma.

However, I have the option RVB colour scale : full / normal.... but the pink/green screen ate still here even when I change the option.

I'm now on the 8.0.2e version, and everythings works fine.

Nogo · October 10, 2017 at 2:00 PM

I can confirm the problem with 8.1.9. It exists on two different Monitors from Dell on a Coolme S905X.

Here the screen is pink/green from the start.

Quote from iskonje

I'm now on the 8.0.2e version, and everythings works fine.

Thanks to iskonje, this solution also works for me for now.

samgarcia · October 10, 2017 at 2:11 PM

it is not a problem with Libreelec, it is a problem with RGB settings with old Tv/Screens.

the reason for 8.0.2.X working fine is because @kszag made a special patch around that time.

but since that version libreelec and built in Kodi have been heavily updated.

I am willing to participate and help out with the development of a patch to Force RGB output on 8.1.X versions. just let me know how I can help

Nogo · October 10, 2017 at 2:16 PM

Just wanted to point to the same problem on the same SoC, where the issue was solved by an option in a new firmware:

incompatible YCbCr and RGB

The author has the opinion, that there might an incompatibilty between the Box and the monitor/TV, so having the option to switch to RGB is solving in his case.

I haven't found this possibility in the libreelec, or am I mistaken?

**kszaq** · October 18, 2017 at 8:23 AM

Quote from Nogo

Just wanted to point to the same problem on the same SoC, where the issue was solved by an option in a new firmware:

Closed source Android firmware is not helpful for us. Resolving this issue requires modifying kernel code.

Switching to RGB 10bit mode should be possible by echo 'rgb,10bit' > /sys/class/amhdmitx/amhdmitx0/attr

JimmySmith · January 5, 2019 at 11:43 AM

Quote from kszaq

Switching to RGB 10bit mode should be possible by echo 'rgb,10bit' > /sys/class/amhdmitx/amhdmitx0/attr

Could I get Full RGB range by similiar command? after this command I have

Jan 05 10:25:29 CoreELEC kernel: hdmitx: video: Bit depth: 10-bit, Colour range RGB: limited, YCC: limited, Colourspace: RGB

on Odroid C2.