Fix OBS Audio Video Sync Drift in Long Sessions

Audio and video desynchronization during long streaming or recording sessions in OBS Studio is a common and frustrating issue, especially when combining a USB facecam with an external XLR microphone routed through an audio interface. This phenomenon, known as sync drift, occurs when the audio and video feeds are processed by different hardware clocks that drift apart over time. This guide provides direct, actionable steps to align your hardware sample rates, adjust OBS settings, and permanently eliminate sync drift during extended sessions.

Match Your Sample Rates Across All Devices

The most common cause of sync drift is a mismatch in sample rates between your XLR audio interface, your operating system, and OBS Studio. If one device is running at 44.1 kHz and another is at 48 kHz, your audio will slowly drift out of sync with your video.

1. Configure your Audio Interface: Open the control software for your XLR interface (e.g., Focusrite Control, Universal Audio, or Behringer driver) and set the sample rate to 48 kHz.
2. Configure Windows Sound Settings:
   • Press Windows Key + R, type mmsys.cpl, and hit Enter.
   • Under the Recording tab, right-click your audio interface and select Properties.
   • Go to the Advanced tab and select 2 channel, 24-bit (or 16-bit), 48000 Hz (Studio Quality) from the default format dropdown.
   • Repeat this process under the Playback tab for your default output device.
3. Configure OBS Studio:
   • Open OBS and go to Settings > Audio.
   • Set the Sample Rate to 48 kHz to match your hardware and Windows settings.

Disable “Use Device Timestamps” in OBS

When OBS uses the hardware clock timestamps from your USB camera or audio interface, clock drift can occur because the two physical devices do not share a master clock. Forcing OBS to use its own system clock to sync the sources usually resolves progressive drift.

1. In the Sources dock of OBS, double-click your Audio Input Capture source (your XLR microphone).
2. Scroll to the bottom of the properties window.
3. Uncheck the box labeled Use Device Timestamps.
4. Click OK.
5. Repeat this step for your webcam or capture card under your Video Capture Device properties if the option is available.

Adjust Webcam Buffering Settings

Video buffering can accumulate latency over long sessions, causing the video to lag progressively further behind the real-time audio.

1. Double-click your webcam source in the Sources dock to open its properties.
2. Scroll down to the Buffering option.
3. Change this setting from “Auto-Detect” to Disable. Disabling buffering forces the webcam to render frames immediately, preventing frames from queuing up and creating a delay over hours of use.
4. Click OK.

Optimize USB Controller Bandwidth

Both high-resolution facecams (like uncompressed 4K webcams) and professional audio interfaces demand significant USB bandwidth. If they share the same internal USB controller, the motherboard may drop data packets, resulting in sync drift.

• Separate the devices: Plug your XLR audio interface into a USB port on the back of your motherboard (ideally a USB 3.0/3.1 port). Plug your webcam into a completely different cluster of ports to ensure they are on separate internal USB controllers.
• Avoid USB hubs: Never run your webcam or your XLR interface through an unpowered USB hub, as this severely restricts bandwidth and power delivery.

Apply a Static Sync Offset (If Needed)

If you have resolved the progressive drift using the steps above, but your audio and video are still consistently out of sync by a fixed margin from the very start of your stream, you need to apply a static sync offset.

1. Click the three dots next to any audio source in the Audio Mixer dock and select Advanced Audio Properties.
2. Locate your XLR microphone source.
3. Adjust the Sync Offset (ms).
   • If your audio is ahead of your video, enter a positive value (e.g., 150 ms).
   • If your audio is behind your video, enter a negative value (e.g., -150 ms).