Measure the real-world timing offset between any audio path and any video path, so you know how much delay to dial in to bring them back into sync.
Example: a Foxtel set-top box feeds an RF modulator that distributes video to the LED screen (via its own tuner), while the STB's audio output is fed to the DSP separately for the PA. Two independent paths — this tool tells you how far apart they've drifted.
Player
Run this on the laptop feeding the test flash + beep into your video source chain (e.g. ahead of the modulator) and audio source chain (e.g. a spare DSP input).
Measure
Run this on the iPad. Point the camera at the video display (e.g. the LED screen) with the mic near the audio output (e.g. the PA speakers).
History
Saved readings per venue/zone. Editable.
Start Player first, then open Measure and hit Start. Stand roughly equidistant from the screen and the speakers for the most accurate reading.