[meherenow]

Hello all,

I've been dual booting as an OpenElec user for many many years, but having upgraded my HTPC system with a Geforce GTX 1070 I've moved over to Millhouse's Libreelec builds mainly for driver reasons.

Anyway, all has been fine, except I have bought a new TV, Samsung 65KU6400U.

All is well when I take the HDMI straight to the TV, I can access all modes.

The problem I have is with my amp, where I want to route through. It's a Sony DN-1050 and it can only handle most 4k refresh rates in 8 bit mode only...

http://helpguide.sony.net/ha/strdn10585/...42768.html

60hz is fine at 3840 x 2160, but I get no picture with 24hz/25hz/30hz etc unless I plug the HDMI in direct to the TV. I can select those refresh modes in the Libreelec options so the HTPC is certainly picking them up.

I've tried creating a custom xorg and messing about with the xorg.conf but to no avail.

I basically need some way to force the output so that it is 8 bit colour only - I imagine that Libreelec is reading the settings given by the TV through the passthrough but then the amp can't pass them back through as it can only handle 8 bit.


The Samsung manual details the modes it can accept if this is any help to creating a working xorg.conf?

Resolution Display format Horizontal frequency(KHz) Vertical frequency(Hz )Clock frequency(MHz) Polarity (horizontal /vertical)
(Dots x lines)
3840 x 2160 24 Hz 54.000 24.000 297.000 + / +
3840 x 2160 25 Hz 56.250 25.000 297.000 + / +
3840 x 2160 30 Hz 67.500 30.000 297.000 + / +
3840 x 2160 50 Hz 112.500 50.000 594.000 + / +
3840 x 2160 60 Hz 135.000 60.000 594.000 + / +

Another issue is that the TV does not passthrough HD audio via ARC.

My graphics card has 2 HDMI outputs, so I can fudge this to work by having one HDMI straight to the TV and one to the AMP, this gives me all the modes plus HD audio. I thought I had my solution with this method...

However, this is a non starter really, because when I want to dual boot into my PC instead of Kodi then there is all sorts of bother with phantom desktops and the audio then only comes through in stereo with Windows, there is no option for surround sound - I have to pysically remove the TV to PC HDMI cable leaving me back where I was originally, with the PC going to the amp and this then gives me 5.1 sound for gaming - hardly ideal I'm sure you'll agree and not something I want the rest of the family footering around behind the back of the HTPC doing!

I don't really want to be buying a new amp, surely there's a way to make this work?



Cheers in advance.

[Soli]

Arc does not support hd audio. And Samsung only supports 2 channel stereo on HdMi inputs.

[fritsch]

I don't get the 8 bit question. With nvidia everything and only thing you can do is forcing the color format via xorg.conf - if that did not help - no idea.

[meherenow]

I don't get the 8 bit question. With nvidia everything and only thing you can do is forcing the color format via xorg.conf - if that did not help - no idea.

This is where I am stuck - what is the method for forcing the 8 bit colour in xorg.conf?

[meherenow]

Arc does not support hd audio. And Samsung only supports 2 channel stereo on HdMi inputs.

I know this - and this information does not help me in the slightest.

[meherenow]

OK, I've done a bit more experimenting, and I can access ALL modes (24hz being the most important) from Windows with no issue, so it looks like possibly a driver issue within Libreelec.

Does anyone have a build with the latest Nvidia drivers injected that I can try?

[Soli]

Arc does not support hd audio. And Samsung only supports 2 channel stereo on HdMi inputs.

I know this - and this information does not help me in the slightest.

Another issue is that the TV does not passthrough HD audio via ARC.

Your wording seemed to imply that you didn't.

It won't even pass through encoded audio, so in this it's not just limited to HD audio in this case. So the "issue" here would not be that the TV doesn't support passthrough of HD audio, but that it doesn't support any passthrough at all.

Sometimes replies aren't meant to (directly) "help you in the slightest", but maybe save you time later on if you were to waste your time trying to chew a metal brick.

[meherenow]

Arc does not support hd audio. And Samsung only supports 2 channel stereo on HdMi inputs.

I know this - and this information does not help me in the slightest.

Another issue is that the TV does not passthrough HD audio via ARC.

Your wording seemed to imply that you didn't.

It won't even pass through encoded audio, so in this it's not just limited to HD audio in this case. So the "issue" here would not be that the TV doesn't support passthrough of HD audio, but that it doesn't support any passthrough at all.

Sometimes replies aren't meant to (directly) "help you in the slightest", but maybe save you time later on if you were to waste your time trying to chew a metal brick.

What I meant was that I need it to go through the amp, BECAUSE I can't get HD audio from ARC.

Anyway, I've posted in the main Kodi 17 thread about this, I no longer think it's anything to do with 8 bit colour as the Windows 10 portion of the dual boot HTPC can display all the modes correctly - I installed the latest nightly Kodi 17 beta for Windows and everything works as it should do, so the problem lies somewhere in Libreelec.

I'd rather not lose all my bookmarks etc from this install so I hope it's just a driver issue needing updated, in the meantime I'll just boot to Windows and use Kodi for UHD material.

[Soli]

I understand, I read it wrong.

I'd try to enable 12bit color in the Windows driver first. If that works, then no problem with colordepth in the receiver.
And I'd get a debug log. And of course, trying custom modelines in xorg. There's a wiki for it, but I'm not sure if it's updated for 4K yet. The Nvidia drivers, afaik, needs custom modelines to properly support 23.976hz anyways.

[meherenow]

I understand, I read it wrong.

I'd try to enable 12bit color in the Windows driver first. If that works, then no problem with colordepth in the receiver.
And I'd get a debug log. And of course, trying custom modelines in xorg. There's a wiki for it, but I'm not sure if it's updated for 4K yet. The Nvidia drivers, afaik, needs custom modelines to properly support 23.976hz anyways.

OK, cheers, I'll get that on my to do list.

The Sony webpage categorically states that the modes I want are ONLY available in 8bit colour, so I assume Windows is picking it up correctly from edid and LE is not.

[Soli]

Window will default to 8bit anyways. But in nvidia settings you can choose 12bit. Dunno if that gives you a true 12bit framebuffer on the consumer cards..but it might be worth trying just to see where that gets you. Of course that 4k60 is going to be limited to 8bit RGB because of the bandwith limitation in HDMI 2.0.

[meherenow]

Window will default to 8bit anyways. But in nvidia settings you can choose 12bit. Dunno if that gives you a true 12bit framebuffer on the consumer cards..but it might be worth trying just to see where that gets you. Of course that 4k60 is going to be limited to 8bit RGB because of the bandwith limitation in HDMI 2.0.

Ah, that make sense why I can get the 4k60 pic then.

So, how do I "make" the Libreelec Nvidia driver output in 8bit?

[Soli]

"Defaultdepth 24" and "depth 24" in xorg.conf.
(Along with other things)
Just google it and the right syntax will show up.

[fritsch]

Which is the default ...

[Soli]

Still worth trying