Find a visible, audible moment
A clap or another visible impact can make a useful reference. For speech, pick a short, clear moment where the mouth is visible and not obscured by a cut.
Do not choose a section with only music, a voice-over or an off-screen speaker. There may be no visual event to align with the audio.
Spread the points across the recording
Choose one useful moment near the beginning and another near the end. Longer spacing makes the pair more representative of the recording, provided the drift is actually steady.
The automatically chosen clips are starting points. Move their positions if a clip contains silence or an unclear face. The app uses the actual times you choose.
Make small changes and replay
Use the slider for an initial adjustment, then the 10 ms controls for finer changes. Turn on replay after adjustment to jump back within the current calibration clip.
The replay distance can be set from 0.5 to 10 seconds. A five-second replay is a useful starting point, not a rule. Turn it off if it interrupts your listening.
Save before you leave
A calibration project lets you return to your selected video and adjustments. It references the source file rather than embedding the footage, so keep the original video available.