For you guys who are having LIP sync issues, I've solved it by connecting my Blu-ray player direct to the Soundbar, rather than the TV.
Blu-ray player = LG UBK90
TV = LG OLED55C9PLA
Soundbar = HW-Q90R
Initial connections. Blu-ray to HDMI-1 on the TV, and TV HDMI ARC to HDMI Arc on the Soundbar.
All sound types other than Dolby Atmos have NO delay problems. When DOLBY Atmos used, i.e. using bitstream input, and auto decode, or any other option to enable Dolby Atmos you get a delay or around 120ms between screen and sound.
Intuitively you would think this should be the connected setup, so with all delay options on soundbar and TV set to Zero, you can't go negative numbers, you will always get a delay. Obviously decode processing times cause a delay within the soundbar.
Changing setup of Blu-ray to HDMI-2 on the soundbar, and keep HDMI ARC on soundbar to HDMI ARC on TV, you get NO delay with Dolby Atmos, as the Soundbar is doing the decoding and sending the video data at the correct time, in this case again with a Zero delay setting on the soundbar.
You are losing Blu-ray to tv connectivity, but most systems can communicate fine through the soundbar with CEC codes anyway, and picture quality should be the same. It's digital init ?
Ideally, I'd want the Blu-ray player connected directly to the TV, but until Samsung sort out delay processing issues, then outputing directly to soundbar is the only work around.
I have a question regarding your remark: "you can't go negative numbers". I have noticed that, but I am guessing that this could fix some of my sync issues. Is this something that is not technically possible, or it is not implemented.
I know this possibility for example exists within VLC Player.
Interested to see your response.
Streaming device = Apple TV 4K with Netflix App
TV = LG OLED65E8PUA
Soundbar = HW-Q90R
I just got my Q90R this weekend. I have pretty much the same connections as SIR-Blade except I have an Apple TV 4K attached to HDMI1 on the TV. I upgraded the soundbar to the latest firmware and I'm using the HDMI ARC connection between the soundbar and TV. I'm having lip-sync issues with Atmos content being streamed from Netflix on the Apple TV. I'm assuming if I plug the Apple TV to the HDMI2 connection on the soundbar this problem should go away. Is there an option to tweek the delay in settings somewhere or any other options to try?