OBS Audio Sync Explained

A practical guide to fixing OBS audio sync by measuring the real offset, applying the right Sync Offset value, and verifying the result on the output that actually matters.

For an OBS sync workflow built around a real returned or recorded output, use the A/V Sync Test & Offset Worksheet. For a subjective comparison through the real screen/camera/mic path, use the AV Sync Reference Loop.

Quick Answer

OBS sync issues are usually fixed-delay problems, not mysterious random failures. The correct fix is to measure the offset, decide whether audio is early or late, and then apply Sync Offset to the source that needs compensation.

What Causes OBS Audio Sync Problems?

Capture card delay: HDMI and SDI capture paths often add more delay than the microphone path.
Camera processing delay: Cameras may add internal scaling, conversion, or output buffering before the signal reaches OBS.
USB mic or audio interface delay: Audio devices can add their own buffering, and the amount depends on driver path and settings.
Monitoring vs actual stream output: What you hear locally is not always what ends up in the stream or recording.
Fixed delay vs drift: A fixed offset can usually be corrected. Drift or changing offset points to a different problem.

Typical: OBS sync issues are most often caused by the video path taking longer than the mic path. Depends on: capture hardware, camera output mode, audio device, and whether you are judging preview, recording, or live output.

How to Fix OBS Audio Sync

Identify whether the audio is early or late.
Measure the delay instead of guessing.
If audio is early, add positive Sync Offset in OBS Advanced Audio Properties to delay that audio source.
If audio is late, reduce any existing audio delay or delay the matching video source with a suitable Render Delay filter. Check supported delay limits and avoid adding more audio delay.
Verify the result using a recording or real output path, not just the preview window.
Iterate in small steps until the result is clean.

Estimate: if you are using a webcam, USB capture dongle, or mirrorless HDMI camera, the video path often needs more compensation than the microphone path. But use measured values as your source of truth.

Common Mistakes

Guessing values instead of measuring the actual offset.
Trusting the preview instead of checking a real recording.
Confusing monitoring latency with stream latency.
Applying the same value everywhere without checking each source path.