What is lip-sync drift and how is it corrected in post?

• A. It is when mouth movements fall out of sync with spoken dialogue; corrected by adjusting ADR timing or re-synchronizing in the timeline.
• B. It's when dialogue levels drift over time due to loudness targets; corrected by limiting.
• C. It's about color grading; corrected by re-recording ADR.
• D. It's when audio sample rate changes during show; corrected by resampling.

Answer: (A)

Lip-sync drift is when the actor’s mouth movements no longer line up with the spoken dialogue as you go through the edited sequence. In post you fix this by aligning the audio to match the visuals so the words line up with the lip movements. The main ways to do this are adjusting the timing of the dialogue in the timeline or re-recording the lines with ADR and placing them to sync precisely. Sometimes a few careful nudges of the audio track are enough to restore perfect synchronization without changing the performance. This isn’t about loudness targets, color work, or sample-rate changes—those solve different issues.