THX1182
Posts: 20
Joined: Fri Oct 11, 2019 6:24 pm

Strange problem on my Rpi 4 4Gb hdmi TV connection..

Fri Oct 11, 2019 7:07 pm

Hi Pi community,

I just recently got my first Rpi device (The Pi 4 4Gb) and encountered a strange problem, when connected to my television. I've read many threads concerning the screen blanking issue, so i started troubleshooting using the tips in the threads, because my TV randomly restarts/reconnects when using Raspbian/Libreelec. The restarts are no longer than 3 seconds long, and it comes across as a handshake issue or something.

I did adjust various settings (as spoken about in threads) in the config.txt... Troubleshooted the power supply (official power supply), hdmi cable etc but nothing seems change the behaviour.

My installation is the NOOBS installation (Raspbian/Libreelec), when Raspbian boots up it shows the desktop and 5 to 7 seconds in, the TV reconnects/blanks for 3 seconds. It then does that ever x amount of minutes, don't know the exact amount of time between those reconnections.

It does the same thing when using Libreelec which is strange, so i decided to use the other hdmi port on the Pi (not the one next to the power input). And it doesn't reconnect/blank the TV... But alas that hdmi port doesn't give sound at all.

So i was wondering is this some kind of handshake issue, between hdmi audio and the Television? Again i tried all almost every troubleshooting method on the web, most apply to the Rpi 3 and not the Pi 4 so don't know if they apply, but i tried boosting hdmi, hdmi safe mode, hdmi group etc... Nothing seems to work.

I even installed xscreensaver thinking it was a sleep issue... But that's most certainly not it.

I'm new to the Rpi and love this little board but am at a loss right now, it's very annoying and can't imagine it's good for the longevity of my Television.

How can i enable audio on the other hdmi port? (Not the one next to the usb-c power input?)... I would like to see if that changes anything.

Hope someone can help me out.

Kendek
Posts: 127
Joined: Thu Jul 25, 2019 4:39 pm
Location: Kaposvár, Hungary

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Sat Oct 12, 2019 6:33 am

Try to set the

Code: Select all

hdmi_preferred=1
in /boot/config.txt to shift audio (and CEC) to HDMI1.

THX1182
Posts: 20
Joined: Fri Oct 11, 2019 6:24 pm

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Sat Oct 12, 2019 11:44 am

Kendek wrote:
Sat Oct 12, 2019 6:33 am
Try to set the

Code: Select all

hdmi_preferred=1
in /boot/config.txt to shift audio (and CEC) to HDMI1.
Hi thanks for helping me out... I added the line but nothing changed when using hdmi 1... Another weird thing is when i plug it into hdmi 0 the TV doesn't see the NOOBS selection screen, blacks out after the rainbow screen and then goes into the last selected OS immediately. Sound is still not working through hdmi 0, so it's useless to use that port when i can't get into the boot selection menu of NOOBS.

Should i try and set it to:

Code: Select all

hdmi_preferred=0 
To see what happens??? Don't understand why it's skipping the boot selection screen when plugged into hdmi 0.

A am reinstalling everything on the SD card as we speak to see if that changes anything, because i messed around with all the config files and want to see what happens with a clean install.

Will keep you updated.

THX1182
Posts: 20
Joined: Fri Oct 11, 2019 6:24 pm

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Sun Oct 13, 2019 1:04 pm

Update!

I think i might have found the culprit! The blanking and/or reconnecting happens, after playing streaming video (either in vlc/chrome) for some strange reason. I have no idea how to log this or share an example of what's going on.

Same thing happens in libreelec... Am going to test out if it happens in other distribution to pinpoint the issue.

What am i supposed to do???? :(

(BTW forgive me for replying to my own post, but i really need some help in figuring this out. If it's a big problem please delete this post and let me open a new topic for this issue i am facing.)

2nd Update

When i turn off hdmi sound the reconnecting does not happen! (In Raspbian). I enable hdmi+analog in Libreelec, and shortly tested the system and no blackouts (although further testing is needed).

Is this some kind of weird hdmi audio handshake issue???

darrow09
Posts: 4
Joined: Tue Oct 15, 2019 2:24 am

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Tue Oct 15, 2019 4:01 am

I am having the same exact issue. HDMI 0 (the one closest to the power) has sound but causes black flashes on the screen every couple of seconds. HDMI 1 no flashes but no amount of changes to the config.txt can get sound through that port. I have also verified that if you play a youtube video while on HDMI 0 but use analog instead of HDMI, the black flashes go away. The moment you enable HDMI for sound it returns.

I have tried flashing it back to previous bootloaders and kernels but same issue persists. The components I got were from this pack:

https://www.amazon.com/Vilros-Raspberry ... 873&sr=8-4

The power supply seems fine as far as output goes, the only other thing would be the hdmi cable but seeing how I'm not the only one, its most likely a software problem.

EDIT: I loaded up Libreelec and it does the same thing however if I drop the refresh rate to 30 instead of 60 the screen flashing stops. I have tried forcing RP4 to use 1080p with 60hz using hdmi_group and hdmi_mode but nothing changes.

darrow09
Posts: 4
Joined: Tue Oct 15, 2019 2:24 am

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Tue Oct 15, 2019 4:24 pm

Finally figured it out. The hint was reducing refresh rate from 60hz to 30hz fixes the issue. So it seems like a bandwidth issue, the cable bandwidth simply couldn't output video at 60hz AND sound. Unfortunately micro HDMI cables aren't as easily available in brick and mortar stores so I had to pay well above market value to walk into best buy and buy one of these:

https://www.bestbuy.com/site/insignia-m ... Id=6167620

and voila, no more problems. As far as HDMI port 1 not having any audio I don't think it's supposed to. I have seen posts on forums that the newest updates should allow that but I have seen no evidence. So stick with HDMI port 0 and get a quality micro HDMI cable or adapter.

Normally I buy my parts separately but amazon had no standalone RP4's only packs. Lesson learned.

jamesjf
Posts: 2
Joined: Sat Oct 19, 2019 10:54 pm

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Sat Oct 19, 2019 11:14 pm

I am having a similar strange problem and new to Rpi. When I first connected to my TV via HDM1 using an HDMI cable and mini adaptor via the mini HDMI port on Rpi 4 (the port away from the power input) I got sound and had no display problems, all was working well every time I booted watch stuff no problems all great and so pleased. Then while powered down I disconnect the HDMI cable from my Rpi, since then I have not been able to get any sound regardless of using different HDMI ports. Does that sound like a cable/adaptor issue? Will be able to test that as I have a new cable arriving in a couple of days that won't require a mini adaptor.

jamesjf
Posts: 2
Joined: Sat Oct 19, 2019 10:54 pm

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Sun Oct 20, 2019 4:07 am

Since my last post, I have resolved my sound issue. Using the same HDMI cable, mini HDMI adaptor, Rpi mini HDMI port closest to the power inlet and the HDMI cable plugged into HDM1 port on my TV. The issue resolved its self after I opened Preferences/Screen Configuration made some adjustments i.e. changed screen ratio and reduced resolution. Once applied the sound immediately returned even after returning the ratio and resolution to original settings the sound remained. Hope that helps someone else with the same issue.

THX1182
Posts: 20
Joined: Fri Oct 11, 2019 6:24 pm

Re: Strange problem on my Rpi 4 4Gb hdmi TV connection..

Tue Oct 29, 2019 2:45 pm

Well i thought i would ditch the other thread i opened because i foolishly thought it was pulseaudio... Whilst pulse isn't even installed by default...

Bought a new hdmi cable (an extender almost the same as suggested) but that did not change the outcome, it's definitely some kind of weird HDMI audio handshake issue... Because it does not happen with analogue audio enabled for some reason... Maybe my tv can't handle the sample rate of the pi or something? Nah i don't believe it... But it is really, really, really..... Frustrating me.

Tried literally everything from changing up cables (5 different ones) to adjusting settings in the config.txt and reinstalling everything... Tried adjusting resolutions settings in raspbian and my TV... The only thing that seems to work is to use analogue audio, which frankly isn't the greatest workaround to be honest...

Again here's a video of what's happening:

https://imgur.com/gallery/n2bRnWE

These are some of the outputs of tvservice:

1 attached device(s), display ID's are :
Display Number 2, type HDMI 0

HDMI events what happens after media is played:

Starting to monitor for HDMI events
HDMI cable is unplugged. Display 2
HDMI is attached
HDMI cable is unplugged. Display 2
HDMI is attached


state 0xa [HDMI CUSTOM RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive

Audio information:

PCM supported: Max channels: 2, Max samplerate: 48kHz, Max samplesize 16 bits.
AC3 supported: Max channels: 6, Max samplerate: 48kHz, Max rate 640 kb/s.
DTS supported: Max channels: 2, Max samplerate: 48kHz, Max rate 640 kb/s.

Please can anyone... Maybe a developer help me resolve this issue? This is driving me absolutely bonkers for weeks now... I can't enjoy my Rapberry pi this way... Maybe it's a TV issue? Maybe it's a raspberry pi issue? I Don't know but i would love to find out.

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