AV Sync Test
Check audio and video synchronization using a synchronized visual flash and audio beep.
Advanced Calibration
Positive = Audio delayed, Negative = Audio advanced.
Check Audio and Video Synchronization with the AV Sync Test
The AV Sync Test helps you evaluate whether audio and video play in sync by combining a precisely timed visual flash with a matching audio beep. It displays the active synchronization offset in milliseconds (ms) and frames, allowing you to assess lip-sync performance on televisions, monitors, projectors, Bluetooth soundbars, and streaming setups.
Whether you’re editing videos, configuring a home theater, or troubleshooting delayed dialogue, this browser-based tool provides a simple way to evaluate audio and video timing. All processing happens locally using your browser, so no audio, video, or calibration data is uploaded or stored.
How the AV Sync Test Works
Running the test only takes a few steps.
- Select your preferred frame rate preset (24, 30, 50, or 60 FPS).
- Click Start AV Sync Test.
- Watch the synchronized visual flash while listening for the matching audio beep.
- Adjust the manual audio offset if you need to simulate or compensate for synchronization differences.
- Review the displayed offset in milliseconds and frames.
- Copy your calibration using Copy Results or select Reset to restore the default settings.
The tool generates a synchronized audio beep and canvas flash every second. Any applied offset is immediately reflected in both milliseconds and frame values, making it easier to evaluate synchronization across different video standards.
If you’re unfamiliar with synchronization delays, What Is Audio Latency? and What Is Round-Trip Latency? explain the underlying concepts.
Understanding Your Results
The AV Sync Test displays several values that help interpret synchronization performance.
| Result | Description |
|---|---|
| Active Offset | Current synchronization adjustment displayed in milliseconds and frames. |
| Frame Rate | Selected video standard, such as 24, 30, 50, or 60 FPS. |
| Frame Duration | Length of one video frame at the selected frame rate. |
| Visual Synchronization Window | Displays the synchronized flash used during the test. |
For example, at 60 FPS, one frame lasts approximately 16.67 milliseconds. A delay close to one frame means the audio and video differ by roughly 16.67 ms. Choosing a different frame rate automatically updates the frame duration calculation.
Frame Rate Presets and Manual Calibration
Different video formats use different frame rates, which is why the tool provides several presets.
- 24 FPS – Common for cinematic content.
- 30 FPS – Frequently used for online video and broadcasting.
- 50 FPS – Used in many broadcast television systems.
- 60 FPS – Popular for gaming, live streaming, and high-frame-rate video.
You can also manually adjust the synchronization offset between -500 ms and +500 ms to test how different timing corrections affect perceived lip sync. This makes the tool useful when configuring televisions, AV receivers, soundbars, or video editing workflows.
If you’re troubleshooting synchronization issues, Why Is My Audio Delayed? and Common Audio Latency Problems provide additional guidance.
Practical Uses for the AV Sync Test
The AV Sync Test can help with many common audio and video workflows, including:
- Checking lip-sync on televisions and projectors.
- Testing Bluetooth soundbars and wireless speakers.
- Evaluating streaming and live broadcast synchronization.
- Comparing synchronization across different frame rates.
- Adjusting manual AV delay settings on media devices.
Because synchronization is measured visually and audibly, repeating the test after changing hardware settings helps verify whether adjustments improved timing.
For additional troubleshooting, HDMI Audio Latency, Bluetooth Audio Latency Explained, and the Audio Latency Test can help identify other sources of delay.
Privacy and Local Processing
The AV Sync Test performs all graphics rendering and audio generation locally using the browser’s Web Audio API and HTML5 Canvas. No calibration settings, audio, or other test data are recorded or transmitted to any server.
Frequently Asked Questions
What does the AV Sync Test measure?
It helps evaluate synchronization between a visual flash and an audio beep by displaying the active timing offset in milliseconds and frames.
Why are frame rates important?
Each frame rate has a different frame duration. For example, one frame at 60 FPS lasts approximately 16.67 milliseconds, so synchronization differences are often measured in both frames and milliseconds.
Can I adjust the synchronization offset?
Yes. The tool allows manual audio offset adjustments between -500 ms and +500 ms for calibration and testing.
Does the AV Sync Test record any audio or video?
No. All processing occurs locally within your browser, and no data is recorded, stored, or transmitted.
Who can benefit from this tool?
Video editors, home theater users, live streamers, gamers, and anyone troubleshooting lip-sync issues can use the AV Sync Test to evaluate synchronization.