Lip-Sync

Lip sync is the matching of recorded speech to the visible movements of a speaker's mouth.^[1] In dubbing and ADR, lines are written, timed, and performed so that the words align with the lip movements on screen, which preserves the illusion that the voice belongs to the character.

Achieving convincing lip sync involves careful adaptation of the dialogue, attention to the timing of key mouth shapes, and precise editing of the recorded performance. The closer the match, the less the audience is distracted, which is why it is a central concern of localization and animation alike.^[2]