Apple TV 4K & LG Dolby Atmos Sound Bar Video Output Issues

Question

Level 1

14 points

Apple TV 4K & LG Dolby Atmos Sound Bar Video Output Issues

Hi all, having a very irritating issue with my Apple TV 4K at the moment.

The Apple TV 4K is connected to the Soundbar (in port) with HDMI 2.0 Cable and then the exact same cable from ARC port on the soundbar to the TV's ARC port. When switching between apps i.e. Netflix, Music, Prime etc, the video output just disappears, and I get a "no input" from TV. Sometimes it comes back after a few seconds, other times I must reboot the Apple TV to get video signal back. This happens when just switching from one movie to another on Netflix as well.

Are there any special changes or setting that I need to change on the on the Apple TV? Currently it is set to SDR, Match Content & Frame Rate. Quick start is on in iTunes Movies and Shows.

I have already replaced both HDMI cables with certified HDMI 2.0 cables as per recommendation from the store.

When using the apps on the LG TV, this does not happen, thus it points to the Apple TV being the issue.

The Hardware Used:

LG TV – 55SM8100PVA

LG Soundbar – LG SL8Y

Apple TV 4K

HDMI Cables – QED HDMI 2.0 Cable with Ethernet

Apple TV 4K, tvOS 14

Posted on Aug 12, 2020 12:36 AM

Reply

Answer 1

LeonGos Author

Level 1

14 points

Aug 12, 2020 4:48 AM in response to Urquhart1244

I had it before the soundbar but fixed it by replacing HDMI cables when upgrading to the Apple TV 4K.

What is difffrent now is the fact that the Apple TV needs to process Dolby Atmos and pass that through as well. At the moment, it seems it might be a bandwith issue, thus asking if there is any specific changes I need to make on the Apple TV now that Dolby Atmos with Dolby Vision is also present.

I have now changed from SDR 60Hz to SDR 50Hz to see if that might make a difference in bandwidth. The issue is fairly inconsistent even if I try and replicate with the same show 15mins apart.

Reply

Answer 2

Aug 12, 2020 5:29 AM in response to LeonGos

it seems it might be a bandwith issue

The same HDMI 2.0 bandwidth (14.4 Gbps data (18 advertised for the cable)) is available to everyone else that isn’t having issues.

… asking if there is any specific changes I need to make on the Apple TV now that Dolby Atmos with Dolby Vision is also present.

No, both should be possible at the same time. That is the point of having this Apple TV 4K device.

Use the YCbCr output, as that is how digital video gets streamed anyway. RGB will not increase the quality for this type of content, but does require more bandwidth. Your TV is quite capable of the conversion; not need to let an external box do that.

Keep your Chroma setting at 4:2:0, as that is how digital video gets streamed anyway. 4:2:2 or 4:4:4 will require more bandwidth without any quality improvement for streaming video.

I don’t know if the HDMI ports on the LG need any configuration? (I thought that was a Sony inconvenience, though.)

I have now changed from SDR 60Hz to SDR 50Hz to see if that might make a difference in bandwidth.

SDR is already a huge bandwidth saver over HDR (-33%).

Yes it makes a little difference (5/6), but not enough for issues. Match it to the TV’s native setting: 60 Hz for NTSC countries, and 50 Hz for PAL countries.

The issue is fairly inconsistent even if I try and replicate with the same show 15mins apart.

HDMI should be working or not work working, depending on setup, consistently. Any inconsistency is pointing elsewhere than HDMI.

Reply

Answer 3

LeonGos Author

Level 1

14 points

Aug 12, 2020 8:07 AM in response to Urquhart1244

Thank you!

Will have a look at all that and test for a while. I think my Chroma settings are set to the highest possible so will definitely change that first.

I don't think there are special settings for each HDMI, but will go into the settings for the TV and have a look as well.

After all the test are done and there is still an issue, I will revert back here!

Reply

Answer 4

LeonGos Author

Level 1

14 points

Aug 16, 2020 10:11 AM in response to LeonGos

Update to the above:

After checking and changing all possible settings on the Apple TV & LG TV, I can't seem to resolve the video output issues. I have checked the recommended settings for the TV. Switched off Deep Color for the HDMI port, changed a bunch of settings. I also double checked all the video output settings for the Apple TV as mentioned above.

I have placed an order for some Club3D HDMI 2.1 cables, hoping they come this week sometime so that I can try that as another option. If that does not solve my issues, I am out of options. Only other thing I can think of is factory resetting the Apple TV, LG TV & Soundbar. Then setup the TV & Soundbar first, after that connect and setup the Apple TV.

Side Node:

Completely lost it last night whilst watching Spider Man Homecoming on Apple TV app and out of the blue, some scenes just started switching to black & white for a second and switching back to color. Stopped the movie 10mins in and started it again on the Apple TV app built into the LG TV and not a single issue. Video and audio quality was absolutely perfect.

I was on the brink of throwing out the Apple TV last night after all the issues the past 7 days.

Reply

Answer 5

Aug 12, 2020 4:14 AM in response to LeonGos

As a test, try to replicate this issue without the soundbar, i.e. connecting the Apple TV to the TV.

Reply

Apple TV 4K & LG Dolby Atmos Sound Bar Video Output Issues

Similar questions