How to Fix OBS Audio Delay So Your Voice Matches Your Lips

Your mouth moves, and a beat later the words arrive. Viewers notice OBS audio delay within seconds, and even a 100 millisecond mismatch makes a stream feel cheap and slightly dubbed. The good news is that almost every lip sync problem in OBS comes from one of four causes, and each one has a measurable fix.

I produce audio for a handful of shows that go out live, and lip sync is the issue I get messaged about most. Here is the routine I use to find the cause, measure the gap and set an offset that holds for a full three hour stream.

Why OBS audio delay happens

OBS does not create the delay. It receives audio and video from different devices, each with its own processing time, and simply plays them as they arrive. When one path is slower, the two drift apart.

In most home setups the video is the slow side. Common culprits:

HDMI capture cards: typically add 30 to 120 ms of video latency, depending on the model and whether it scales the signal.
Mirrorless cameras over HDMI: the camera's own processing adds another 50 to 150 ms before the signal even leaves the body. If you followed our guide to using a mirrorless camera as a webcam, expect to need an offset.
Webcam frame buffering: USB webcams often hold a few frames before passing them on.
Bluetooth audio: a Bluetooth headset microphone can lag 150 to 250 ms, which pushes the problem in the other direction.

A fifth cause behaves differently. If the sync is perfect at the start and gets steadily worse over an hour, you have drift, not delay. That is a sample rate problem, covered further down.

Measure the gap before you touch any setting

Guessing an offset wastes an evening. Measure it instead.

Start a local recording in OBS with your normal scene, camera and microphone.
Face the camera and clap sharply three times, about two seconds apart, with your hands clearly in frame.
Stop the recording and open it in any editor that shows a waveform.
Step frame by frame to the exact frame where your palms meet. Note the timecode.
Find the start of the clap spike in the audio waveform. Note that timecode too.
Subtract. At 30 fps one frame is about 33 ms; at 60 fps it is about 17 ms.

If the audio spike comes before the hands meet, your audio is early and needs delaying. Average the three claps. A typical result for a camera on a capture card is somewhere between 80 and 200 ms.

Setting the sync offset in OBS

Once you have a number, the fix itself takes about a minute.

In the Audio Mixer, click the gear icon on any source and choose Advanced Audio Properties.
Find the Sync Offset column for your microphone.
Enter your measured delay in milliseconds. A positive value delays the audio.
Record another clap test and check it the same way.

Set the offset on each audio source that needs it, not on one master. Your mic might need 140 ms to match the camera, while game audio coming in through the same capture card as the video is already in sync and should stay at 0. Desktop audio from browser alerts usually needs nothing either.

Setup	Typical mic offset
USB webcam, USB mic	0 to 60 ms
Mirrorless camera via HDMI capture	100 to 200 ms
Camcorder via HDMI capture with scaling	150 to 250 ms
Webcam, Bluetooth headset mic	Video often needs delay instead

Treat the table as a starting point only. Two people with the same camera can measure 40 ms apart because of different cables, capture firmware or output resolution.

When the video needs the delay instead

If your audio arrives late, which is the usual story with a Bluetooth headset, OBS cannot pull the audio forward. You have to slow the video down to meet it.

Right click the camera source, choose Filters, and add a Render Delay filter under Effect Filters. Set it to your measured gap, up to the 500 ms limit. Better still, replace the Bluetooth mic with a wired one. Bluetooth latency also varies from session to session, so a fixed offset that worked on Tuesday may be wrong by Friday.

Fixing drift that gets worse over time

Drift usually means your devices disagree about sample rate. A USB mic running at 44.1 kHz while OBS runs at 48 kHz gets resampled constantly, and small timing errors pile up over a long session.

In OBS, go to Settings, then Audio, and set Sample Rate to 48 kHz.
In your operating system's sound settings, set every input and output device to 48 kHz as well.
Restart OBS after changing these. The change does not fully apply until you do.
For a capture card or camera source, try toggling Use Device Timestamps in the source properties and run a 30 minute test each way.

Before you blame drift, rule out a struggling machine. If the Stats panel shows rendering lag or skipped frames, the video is falling behind because the computer cannot keep up, and the fix is a lighter encoder preset or lower output resolution. Our guide to stream bitrate settings covers the encoder side.

Do not tune sync by ear in your headphones

The most common advice I see is to watch the OBS preview, listen through your headphones and nudge the offset until it looks right. I tell people not to do that.

Your monitoring path has its own latency. The preview window is rendered separately from the encoded output, and the audio you hear through Audio Monitoring passes through your headphone driver with its own buffer. What looks synced in the preview can be 50 ms off in the actual stream, and you will never see it from your chair.

Always judge sync from a recording or from the stream itself, watched on a second device. A local recording uses the same pipeline as your stream output, so it tells you what viewers actually get. It takes two minutes longer and saves you from tuning against a moving reference. While you are in the audio settings, it is also a good moment to recheck your microphone gain, since clipped peaks make clap spikes harder to read.

Frequently asked questions

Why is my audio ahead of my video in OBS?

Your camera path is slower than your microphone path. Capture cards, HDMI cameras and webcam buffering all add video latency, while a USB mic sends audio almost instantly. Add a positive Sync Offset to the mic in Advanced Audio Properties to delay it to match.

What is a normal sync offset for a webcam in OBS?

Most USB webcams need between 0 and 60 ms on the microphone. HDMI cameras through a capture card usually need more, often 100 to 200 ms. Always measure your own setup with a clap test rather than copying a number.

Why does my OBS audio go out of sync after an hour?

That is drift, and it usually comes from mismatched sample rates. Set OBS and every audio device in your operating system to 48 kHz, then restart OBS. If it continues, check the Stats panel for rendering lag, which means the computer is overloaded.