Drifting audio sync one day to the next

I know that there are other threads addressing various sources of audio sync issues. I’m not sure if this is the same issue and didn’t want to derail those conversations, but feel free to merge if desired.

My setup is ATV4k → Denon AVR → LG CX. On the ATV I’m using Infuse (duh) and have both Match Range and Match Frame Rate enabled. I am using these AV test files, primarily at 60fps and 24fps.

My audio was in-sync for a while, until the other day I noticed something was off. I used those test files and took 240 fps slo mo video of my TV, and found it was off by about 2 frames at 60 fps. I made the audio delay adjustment on my AVR and it looked good.

Then the next day, something was off again. Repeated the test and now it’s off 3 frames the other direction. I feel like I’m chasing my tail.

To be fair, I’m not sure that Infuse is the issue. Could my TV be adding inconsistent processing delays (I have disabled all “smart” features)? Could my AVR handle different formats with different delays (seems unlikely since I’m using the same test files with different results)? Or something with the ATV and tvOS16 bugs?

Any thoughts appreciated.

Two or three frames at 60fps is an audio sync mismatch of only 33-50 milliseconds… I doubt that much professionally released content actually matches up that precisely to begin with.

Admittedly I’ve done a lot of damage to my hearing over the years (:wind_face::airplane::helicopter::headphones::stadium:), but anytime I’ve noticed lip/audio-sync issues and obsessed about fixing them I’ve never needed to be any more precise than could be achieved by jumps of 250 milliseconds in either direction (and probably 500 would have worked just as well since by that point I was likely making myself hear things that weren’t actually there).

Unless you’re requiring scientific accuracy I’m not sure it’s worth going through the effort of using super-slow-motion to help you fine tune things.

Now I only bother consider making audio delay adjustments when I notice obvious issues watching content at normal speed. :man_shrugging:t2:

If the sync is drifting day to day, there very well may be some environmental factors at play.

In addition to adjusting audio sync on your receiver, Infuse also has a built-in audio delay option you can also use. To use this, you can start playing a video, swipe down, and navigate to the Audio tab. This might be a quicker option if you are having to make frequent adjustments.