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QR Time Sync

Flash millisecond timestamps as QR codes to sync multi-camera rigs — film the screen, decode the footage, align every recording to one clock.

QR sizeLarger is easier to decode from a distanceShow time readoutHuman-readable clock under the code

How to use it

1Set screen brightness to maximum and turn off auto-brightness.
2Tap Start — the display flashes the current time in milliseconds as a QR code, updated every screen refresh, and keeps the screen awake.
3With every camera already recording, hold the screen in front of each lens for 3–5 seconds, close enough that the code is sharp.
4Repeat at the end of the session to measure clock drift on long recordings.
5Run the decoder script (Python + OpenCV) on each camera's footage — it decodes the stamps and prints each camera's clock offset and drift, aligning all recordings to one clock.

Every camera films the same screen, so display latency cancels and the relative sync between cameras is sub-frame after the decoder's linear fit — the same technique large egocentric-video datasets use to align head-mounted and tripod cameras. Quick link for the field: lavignelabs.com/qr-sync