N2 LG OLED C1 4k HDR Content - No Signal on CE20

[feerlessleadr]

Hi - My N2 has been in use w/ CoreELEC for quite a few years and it has been awesome, so thanks for your hard work on this awesome software.

I recently did a clean install of CE20 on my N2 to emmc using the HK emmc to microsd tool, and everything went very smoothly. I got everything setup on my kodi install (E4K, embycon, embuary skin, etc.), and then realized that no 4k videos would play. Whenever I clicked on a 4k video to play, my C1 would show the ‘painting’ screen (which is essentially the no signal screen). As soon as I hit back on my remote, I would drop back into Kodi. 1080p and below would play fine.

I knew the HDMI cable wasn’t broken, as I recently purchased it in the last 2 months, and have been playing 4k HDR content on my 19.5 install on my N2, as well as My Shield pro runnig Kodi Android 20 (which I had temp swapped in for my N2 for a few days).

As I always do when reporting a problem, I created a fresh kodi profile to confirm that my setup wasn’t causing the issue, and low and behold, the 4k & 4k HDR videos started to work. I then installed each addon individually, and tested after each was setup that my 4k files continued to play, until I had everything installed the way I normally do. All of my 4k files continued to play no problem. That was last night. Tonight, I go to play a 4k movie, and I am having the same issue. The only thing that happened to the box since it was working yesterday was that it was turned off overnight, no changes to addons, etc.

Here is a log of my current profile w/ everything setup the way I like where I try to first play a 4k movie from emby for kodi’s synced database. Then just to be sure, I try to play a 4k HDR tv show direct over my network on the N2, bypassing emby all together. Both outcomes are the same (no output signal on the TV):

https://paste.ubuntu.com/p/3XSyRKmSfG/

Here is the output of ‘dispinfo’ when trying to play a 4k file on the N2:

http://ix.io/4nOl

Now - even on a fresh kodi profile, I am unable to play 4k content on CE20 on my N2:
https://paste.ubuntu.com/p/hh3YSYwPNS/

Any help would be appreciated.

::EDIT:: Maybe this is hardware related, as I just did a clean install of the latest 19.5 nightly, and with no addons installed (other than the sftp addon to access my vids) I still can’t get 4k vids to play. I plugged in my shield pro using the same setup/cables/tv, and 4k plays no problem.

[Portisch]

Try to limit colour depth in expert display settings to 10 bit.

[noggin]

Don’t assume that a cable working correctly with one device will work correctly with another device. Don’t assume an HDMI input that works with one device will work with another.

1. There are different bandwidths that can be used to send the same content over HDMI in subtly different formats. For example 4:2:0 10-bit 2160p59.94 takes a LOT less bandwidth than 4:2:2 12-bit 2160p59.94 and the former will pass over cables that cannot take the latter, both are valid HDMI 2.x formats.

2. Some TVs have HDMI inputs with different levels of UHD support (lots of Sony displays have cut-down support on HDMIs 1 and 4 and full support on HDMI 2 and 3 for instance, some TVs don’t have full support at all) AND on some displays (and AVRs) you have to specifically enable the higher bandwidth (aka ‘Enhanced’ or ‘4:2:2’) modes to enable them to work. (I had to enable both my Sony TV and my Denon AVR to work with the higher bandwidth modes for instance)

What’s confusing is that two devices can use totally different modes to output the same content. To almost all end users the difference between 4:2:0 10-bit and 4:2:2 12-bit at the same frame rate and resolution is minimal - but some sources only use one or the other - and the higher bandwidth required for the latter can cause you issues - either with cables not supporting the higher bandwidth, or with inputs on TVs and AVRs not supporting it (or not having support for it enabled in the TV and/or AVRs menus)

(Also note that 4:2:2 is only supported in many iterations of the HDMI standard in 12-bit mode - not 10-bit - and that 4:4:4 / RGB aren’t supported at anything other than 8 bit at the higher frame rates in UHD. 4:2:2 12-bit is the only format that supports >8 bit and thus decent HDR at all UHD frame rates - but it requires higher bandwidth connections than 4:2:0.)

Also - when you are ‘on the edge’ with a cable - some HDMI sources may be slightly better engineered electrically than others - so a cable that ‘just’ works fed with one may ‘just not’ work with the other. (Welcome to high bandwidth edge cases)

First thing I do whenever I have an issue like this is power cycle the TV, take any AVR out of circuit, check which HDMI input on my TV I’m using, and also make sure the cable I’m using is up to the job.

[feerlessleadr]

Thanks - this is very strange. I know for 100% certainty that my cables are not the issue in terms of bandwidth, as they are high quality monoprice 48Gbps cables that were working with this very box watching this exact 4k content up until Friday night when I went to bed.

Here is my setup: I have my N2 plugged into a Sony HT-A9 surround sound system w/ a 6ft Monoprice 48Gbps HDMI cable, then the A9 is plugged into my C1 (HDMI2 input, which is HDMI2.1) w/ a 40 ft Monoprice 48Gbps HDMI cable (this is a fiber optic hdmi cable since the distance is longer, see here - Monoprice 8K SlimRun AV Ultra High Speed HDMI Cable 40ft - AOC 48Gbps Black - Monoprice.com).

When I plug the box directly into my TV w/ my main HDMI cable (the one that normally goes from my TV to my HT-A9) and remove my Sony HT-A9, the N2 will output 4k. I also confirmed that when the N2 is plugged into the same TV HDMI port w/ my shorter HDMI cable (also 48 Gbps from monoprice, which currently goes from my N2 to my HT-A9), it will output 4k. So it appears that the N2 now doesn’t like my HT-A9 for some reason.

The A9 is more than capable of outputting the 4k files I’m trying to play (it is capable of 4k120 HDR/DV passthrough), and was working with the N2 on Friday night (and continues to play the same high bandwidth files on my Shield, including DV files). Nothing changed w/ the HT-A9 between Friday night and Saturday when I upgraded my N2 to CE20 (not saying that CE20 had anything to do w/ this, since now even 19.5 nightly doesn’t work). I’m stumped.

[noggin]

Does your LG give you any information about the precise signal format it is receiving? That might be useful additional information.

Active cables also add a lot more into the mix as they are not as straightforward as passive cables - but if your N2 and your LG TV work with a direct connection between the two then that’s a good sign.

The order you switch things on is important when you use HDMI - you want the TV to be powered on first, then the A9, and then finally the N2 - as the A9 will add EDID data to that received from the LG TV when the N2 requests EDID (if it does)

There are a couple of Expert options in CE for output formats like 4:2:2 - it’s worth trying those.

Are you running your UI in 1080p and just whitelisting UHD modes - or are you running the N2 in UHD/60Hz as standard? 2160p50-60 is much trickier in some situations than 2160p23.976-30 - so that might also be something to consider.

What error message does your LG display when it fails to display a picture? (It may be worth posting CE logs too)