HDR via non-HDR capable AVR to HDR TV yields dark picture

Hey everyone - first of all, I apologize in advance for adding another 4K HDR post to the massive pile of posts on this forum already. However, I have spent well over an hour reading through hundreds of posts and the wiki and I’m not confident I have correctly interpreted my issue and what my options are.

If someone smarter than me could check me out on my understanding before I start going out shopping for a new AVR/TV/Splitter, I sure would appreciate the help / sanity check.

Anyways, longtime member going back to the early days, but I’ve been on an Odroid-C2 the last few years and just bought a 4K+

Essentially, my issue is that HDR 10-bit content sent through the Onkyo comes out too dark and my TV doesn’t even see the HDR flag (possibly the Vero is auto-switching HDR off? Not too sure)

Here is my setup:

Vero 4k+
Onkyo TX-NR727
Samsung KU6000

The Onkyo is about 5 years old and while it supports 4K passthrough, I think it can’t survive with HDR. It does process TrueHD and DTS-HD/MA which I like.

The Samsung KU6000 has HDMI UHD Color options for HDR support (but only on HDMI 1 input)

If I connect my Vero 4k+ direct to the Samsung and enable the HDMI UHD Color, I get the 4k resolution and the HDR flag is shown on the Samsung and the picture looks great. However, I then run into a brick wall with all the issues around getting HD audio to work and I’m fairly confident that there is simply no hope of getting TrueHD via HDMI and the ARC. It seems pretty clear that Optical does not support TrueHD so there’s no hope there.

If I connect the Vero 4k+ through my Onkyo and output it to HDMI 1 on the Samsung, my audio works as expected, but I do not get the HDR flag showing on the Samsung anymore and the video looks too dark.

I think this means I really only have two options if I want to have both HDR output to my Samsung TV and still have HD audio support?

  1. Buy a new AVR that can properly handle HDR content passing through
  2. Buy an HDMI splitter so I can send the Vero4K+ signal to my AVR for Audio and to the Samsung for Video

Both of these are going to require spending more money than I really want to do at this stage so I want to make sure I have correctly assessed this?

The only question that I can’t really answer is if it is possible to setup, or tweak, the Vero 4k+ so that I solve the issue of HDR content being too dark? That would give me an interim solution to playback my HDR content and have it look at least as good as SDR until I can fork out the cash for a new AVR?

It looks like you’ve figured out the real problem (Onkyo not passing HDR data), but that turns it into a different problem, which results in the dark picture. The new problem is whether the 4K is sending HDR despite the fact that it can’t pass the Onkyo. My guess is that the 4K is seeing the HDR-capable TV through the Onkyo, even though HDR can’t pass through. You’ll need to post logs so that we can see if that is the case.

What you really want as a temporary solution is for the 4K to send SDR, which should pass through the Onkyo intact, and the TV should also handle it, and show the correct picture. There’s no setting in Kodi to force HDR or SDR, but there might be a way to do it via the shell.

But, if the 4K is already sending SDR, then perhaps you need to adjust some setting on your TV?

Your analysis is spot on. The Onkyo probably does not recognise the HDR capability of the Samsung so doesn’t tell Vero about it. Also, although it’s ‘4k’, that is probably limited to 4k30Hz at 10 bits and, perhaps, 4k60Hz at 8 bits. cat /sys/class/amhdmitx/amhdmitx0/edid will confirm this.

You are right about your long-term options. Short-term, you can adjust the brightness and contrast of HDR material to get a better-looking picture.

I might be in the same boat with my denon, although I’ve only got 1080p devices connected to it so far. A lot of material on the vero just seems way too dark:

osmc@vero4k:~$ cat /sys/class/amhdmitx/amhdmitx0/edid
Rx Brand Name: DON
Rx Product Name: DENON-AVRHD
Manufacture Week: 0
Manufacture Year: 2012
Physical size(cm): 160 x 90
EDID Version: 1.3
EDID block number: 0x1
blk0 chksum: 0xe0
Source Physical Address[a.b.c.d]:
YCC support 0x03, VIC (native 16):
ColorDeepSupport 0xb8 10/12/16/Y444 1/1/0/1
16 31 32 34 5 20 4 19 3 2 18 17 7 6 22 21 1 15 14 30 29 35 36 37 38
Audio {format, channel, freq, cce}
{1, 7, 0x7f, 0x07}
{7, 5, 0x1e, 0x00}
{2, 5, 0x07, 0x00}
{11, 7, 0x7e, 0x01}
{10, 7, 0x06, 0x00}
{12, 7, 0x7e, 0x00}
{9, 5, 0x02, 0x00}
Speaker Allocation: 0x5f
Vendor: 0xc03
MaxTMDSClock1 225 MHz
RR_Cap: 0
LTE_340M_Scramble: 0
checkvalue: 0xe0e20000

I had the same problem with my old Marantz AVR. The splitter I got does the trick and this was much cheaper than getting a new AVR. See here for details: Audio surprise - #4 by grahamh

Thanks everyone. I opted to upgrade my AVR rather than try to fight around with these issues.