Random Audio–Video Desync on Mac Mini M2 (OBS 32.x, 4K Recording, Low CPU Usage)

Jonathan Konrad

New Member
Hi everyone,
I’m running OBS on a Mac Mini M2 (8 GB RAM), and I’m having a frustrating, inconsistent issue with audio–video sync drift when recording.

Setup:
  • Camera: OBSBOT Meet 2 (USB 3.2)
  • Audio: Boya Wireless Mic (USB 2)
  • OBS version: latest (as of post date)
  • Resolution: 4 K recording
  • CPU usage: rarely above 6–8 %
  • Firmware and drivers: all up to date (latest OBSBOT Center, firmware updated)
  • Auto exposure and gesture control disabled
  • USB cable supports 40 Gb/s
Issue:
Some days everything works flawlessly, even during 15-minute recordings. Other times, the video gradually lags behind the audio — it looks like the video slows down, while the audio keeps normal speed. Restarting the Mac or OBS sometimes helps, but not always. The desync can appear after one minute or not at all.

It feels random — no pattern I can find — and OBS never shows high CPU usage.

What I’ve tried:
  • Replacing the USB cable
  • Updating firmware and OBSBOT Center
  • Turning off all AI and gesture features
  • Checking sync offset and encoder settings
  • Disabling auto exposure and auto focus
At this point, I’m not sure if this is a camera-side issue, a USB bandwidth problem, or something about how OBS handles 4 K on macOS.

Has anyone seen similar behavior or found reliable fixes for intermittent AV desync on Apple Silicon?

Thanks in advance for any insights.
 

Jonathan Konrad

New Member
Intermittent AV sync drift suggests clock differences. Try matching all audio and video sample rates to 48 kHz and disabling OBS's source buffering.
OK, nubie question here; I can find the audio and it's set to 48 kHz. I can't find any setting for clock on the video. I checked everything and no buffering is on. I did have "Downmixing" checked for the audio so I took that off and just picked a channel. Just to see if anything changed, I choose "Metal" instead of OpenGl even though it is experimental. I'll have to try a few recordings and see if anything shifts. thanks again for the tip.
 
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