Audio/Video Sync Test Video
A white flash and a matching beep fire at the exact same instant, once per second, with a running frame counter in the corner, so any lip-sync or A/V drift becomes visible and measurable frame by frame.
What these files actually are
The flash and beep are driven by the same underlying timing condition in the source, so any offset you perceive when playing this file back is happening downstream, in your player, pipeline, or hardware, not baked into the file.
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DownloadAudio/video sync test (MP4)MP4 · 368 KB VirusTotal report
Are these files safe to download?
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Specs
- Resolution
- 1280x720
- Cue
- White flash + 1kHz beep fired together every 1 second
- Readout
- On-screen frame counter (25fps)
- Duration
- 10 seconds
Common use cases
Streaming pipeline latency checks
Play through your streaming or transcoding setup and freeze-frame to count how many frames audio leads or lags video.
Bluetooth and wireless audio testing
Check for the audio delay commonly introduced by Bluetooth speakers, soundbars, or wireless headphones.
Video editor and NLE verification
Confirm your editing timeline keeps imported audio and video perfectly aligned after cuts, exports, and re-encodes.
Frequently asked questions
- How do I measure the drift precisely?
- Step through frame by frame around a flash and note the frame counter when the beep is audible versus when the flash appears; each frame is 1/25th of a second.
- Is the flash/beek offset baked into the source file?
- No. Both are triggered by the exact same condition during encoding, so the file itself is perfectly in sync.