Denon X-3400H --> 4k video is unreliable (black screen) [Solved]

I’m still having unreliable video output from my Denon X3400H (mid-end newish denon) on 4k movies, even with the latest April update. Sometimes it works and sometimes I get no video, only audio. Yesterday I tried to start all my movies and they all worked. Tonight I tried again and the first movie failed immediately. I have bought new certified cables, disabled video processing in the Denon, used the HDMI input closest to the output as recommended by Denon, HPD setting in Kodi, etc…

Before the April update I used the modified rc.local as described in other thread, but the result is the same.

If I reboot the system a few times, I get like and things work, but it seems to be random.

Here’s a partial log (full log was too big and couldn’t be uploaded by grab-logs, so I kept the startup info and the portion of the log when I try to start the movie, twice):

I hope this helps.

I also, anecdotally experienced video with no audio, but I don’t have a log for it.

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Hard to tell from partial logs, but have you installed other packages on the system?


I believe I installed only rsync, but to be sure the list of installed packages is here:

Can you post a full set of logs? A fresh boot will put you under the 10M limit.

When you get sound but no video, does the TV show no signal or can you bring up the OSD? Did you change rc.local or are you relying on the HDR auto switch option?


I’ll give it a shot later on today. The tv shows no signal (the message says something like “the input from avr x-3400H has no video”). I cannot bring-up the OSD of osmc.
I can enter the menu of the Denon (this activate the video to the TV) and in the hdmi information page, where usually there is the info about resolution, color space and bits, I just get a bunch of “---- - ----”
Once I started a movie with that information page already on and I saw, for an instant, the info going from 1080p (gui resolution), to 4k 10 bits to “-------”

I’m using the auto-switching. I used the rc.local until the updated, but the result is the same. I haven’t posted before, because I wanted to wait for the update, in case it foxed the problem.

The auto switching is sporadic and we cannot always tell when to switch just yet.

It sounds like the problem occurs when Vero 4K does detect and switch in to 10-bits.

So in theory if you disabled it, you’d get 8 bit output but would work every time. This would suggest to check cables etc between the devices.

Yes, I should have mentioned. 8 bits work every time. I just replaced the cable osmc-receiver with a certified high speed cable but that didn’t fix it.
The cable denon-tv is long, so I had to buy a fairly expensive active cable to get the proper 4k signal from my previous box (Nvidia shield), but after that the shield was ok. Next step up in cable is fiber optic. I’m ok in spending $150 on a fiber optic cable if there is good confidence that that is the problem, but according to spec, the cable I have should be already ok.

I’m now having doubts about my cable. This is the model:
Monoprice 4K High Speed HDMI Cable 25ft - CL3 In Wall Rated 18Gbps Active Black (HOSS) - length is 40 ft

FWIW I have the same receiver and monoprice high speed HDMI cables as well. Max length is 6 feet and have no issues like you are describing. 40 feet is pushing the limits of 4K though so I’d suspect the cable may very well be the weak link. Just wanted to chime in as I have the same receiver and Vero 4K hardware.

Thanks! That’s very encouraging that with the same hardware you have no issues.
So I’m tempted to order this one:
the issue of course is cost.

edit: I ordered the fiber optic cable. I’ll update the thread over the weekend. I really hope this is it.

On long HDMI runs there is bound to be some issues. I seem to recall 5m or 15 feet as the theoretical max for full 4K over HDMI. I’d definitely give the fibre a shot as I suspect it would work better. Fibre is immune to any interference and stable at very long runs, many 1000 feet actually. Good luck!

Yeah… when I designed the system 8 years ago, I didn’t foresee this 4k thing, I guess. I had much more equipment (blu-ray player, video processor, dvr, HTPC, etc…), so I decided to put all the wiring in the back of the room and the equipment in a rack, to leave the front wall less cluttered and with less distracting LED lights.

I never thought I would run in this long HDMI cable issue. Now that my only equipment are receiver and vero 4k, I would have made a different choice. But I’m stuck, because rewiring everything, including 7.1 in wall speaker wires, ethernet, internet provider cable, etc… is not realistic.

Finally got full logs:

I got other hardware but also sometimes no display when watching 4K stuff, got a 2.0b Onkyo AVR and 2.0b certified cables (length avr-tv is 3m and the rest 1m)

I’ve had this with multiple avr’s and cables like mentioned before.
Switched cables with my Shield and x800 UHD Bluray player, doesn’t make difference so should be something with the Vero.

for me when it works it works. If one 4k movie starts ok, than I can start 20 movies in a row with zero problems. But sometimes I turn on the TV and none of the 4k movies works until I reboot.
While I will try a new cable, I would expect that a cable problem would show up if I continuously start and stop 4k movies, but when the system works I can try all night and it would never fail.

When it doesn’t work also, no matter how many times I try to start and stop the movie, only turning on and off the system would fix things.

It works for me quite often, but the problem is always when it switches from 8bit to 10bit or vice versa.

I did some more testing and it is not good news…
I ended up ordering two cables:

I just tested the Furui cable, connecting the Vero 4k directly to the TV (to remove the Denon receiver from the equation), and a 4k movie started correctly only 2 out of five times.

I’ll test the monoprice cable tonight (which would not be a very good solution as it doesn’t support CEC) and report back.

so… turns out that the fiber optic cables don’t work any better than the active cable I already have. They’re actually more likely to cause the no video problem.

I also found another thing: if I connect the Vero 4k directly to the long cable I have a lot more issues and very rarely movie starts correctly.
Instead, in the normal use case, when I use the vero connected to the receiver, things are like I described before: it works most of the time, but every few days it starts failing and I need to reboot a few times.

I know that this isn’t scientific, but maybe the problem is in the vero. I’m saying this because I tried three cables already (two of them are fiber optic, for which 50ft should be no sweat at all), and in all cases I have issues, and the issues are much worse when the vero is driving the cable directly, instead of the receiver.

Also, when the problem happens, according to the receiver OSD, the vero is not sending a video signal.

I’m thinking to buy an extra short certified cable (1ft) to connect the vero to the receiver and see if this helps. I’m not sure what to do next.

Sam, did you look at the full logs? Anything noticeable?


The reason using the long cable from the AVR works better is it’s travelling a shorter distance from the last source. This won’t be an issue with the Vero 4K itself.

The Vero will be sending a signal, but the drive strength won’t be strong enough for it to be received by the projector.

I had a similar issue in 2012 when using cables over a long range, but fortunately using good quality cables resolved the issue for me.

One idea would be to disable Adjust Refresh Rate temporarily. Does it improve your ability to start films? You’ll need to set the GUI to 4K manually or you won’t be testing output at 4K however. If it helps things, then it rules out a Vero issue entirely.


Hi Sam thanks. I’ll definitely try the 4k gui. Would the GUI be in 10bits? 8 bits always works.

I actually don’t understand your comment about the shorter distance. I’m actually using the same long cable, so same distance. When connected to the receiver, with the vero driving a short cable to the receiver, things work much better than when the vero drives the long cable directly.

Anyway, thanks for your help. I’ll run the test you suggest and let you know.