Solving playback issues

[Mjross33]

Audio Lag on 4k content. Nothing seems to work. Volume mode - off, no improvement. Switching to stereo - no improvement. Really frustrating. 

[StreamerUser]

Which model Roku and TV do you have?

How is your Roku connected? (e.g. directly, or through a switch/AVR).

Have you adjusted the lipsync settings in the LG's sound settings? (Settings/Sound/AV Synch adjustment).

[Mjross33]

LG UM6900PUA

Ultra 4660X2

Marantz NR1608 AVR

The issue is worse on 4K content. I tried the LG sync adjustment but it doesn't have an impact. 

[StreamerUser]

If you are connecting through the AVR, connect the Roku directly to the TV (with ARC to the AVR) and see if the issue persists.

Or vice versa if connecting to the TV - connect through the AVR instead.

Make sure you enable CEC/verify any lipsync settings in the AVR.

Make sure you enable BYPASS when enabling AV Sync adjustment in the LG.

FYI, LG has a history of AV sync issues (specifically, delayed audio) in every model year for years, which they are continuously attempting to address with firmware updates.

You should probably refresh the HDMI/CEC (including lipsync) handshakes:  power everything off for several minutes, then power your AVR completely on, then power your TV completely on, then power your Roku on.

[Mjross33]

Did some more trials, including using ARC (Roku->LG TV->Marantz AVR). Did not make a difference.  Also did the power off, reset the handshake thing with no effect.  I have noticed that there is no delay on YouTubeTV, 100ms delay on HBO and Netflix and 200ms delay on Prime.  Would HDR or 4K make the issue worse?

[StreamerUser]

@Mjross33 wrote:

Did some more trials, including using ARC (Roku->LG TV->Marantz AVR). Did not make a difference.  Also did the power off, reset the handshake thing with no effect.  I have noticed that there is no delay on YouTubeTV, 100ms delay on HBO and Netflix and 200ms delay on Prime.  Would HDR or 4K make the issue worse?

They could, depending.  You could always manually select 1080p in your display settings and test.

Make sure you have the latest firmware for all the devices:

LG UM6900PUA:  05.00.15 (2/24/21)

Roku 4660:  9.4.0-4200 (12/20)

Marantz NR160:  unknown (check via the UI)

Verify you have BYPASS enabled in the sound settings on the LG when using ARC, etc

Verify your AVR's lip/AV sync settings.

What happens if you switch Settings/Audio/HDMI/Auto detect to PCM Stereo? And then back/direct selection of DD+/DTS?

Have you tried different cables?

[Mjross33]

Tried a different cable, changed the audio to PCM then DD+/DTS, checked all the firmware....no improvement.