How do you avoid lip-sync issues when the presenter is on a large screen (IMAG)?

Lip-sync problems happen when the video processing chain introduces latency (delay). The camera captures the presenter, the signal is processed through a switcher or scaler, and by the time the image reaches the IMAG screen, it's anywhere from 1-5 frames behind the live audio. The audience sees the presenter's mouth move on screen a split second after they hear the words, which is distracting and looks unprofessional.

The fix is to add a matched delay to the audio signal so it arrives at the audience's ears at the same time as the video image appears on screen. The audio engineer coordinates with the video team to measure the exact video processing delay (usually in milliseconds), then applies a corresponding audio delay. This synchronization must be rechecked whenever the video signal chain changes during the event.