ADR (Automated Dialogue Replacement)

ADR, short for automated (or additional) dialogue replacement, is the process of re-recording dialogue after filming. The actor watches the scene in a recording studio and performs the lines again in sync with their on-screen performance. It is also called looping, and in some regions post-sync.

Productions use ADR for several reasons. The original recording may be unusable because of traffic, wind, aircraft, or equipment noise. A line may need to change for clarity, story, or legal reasons. And sometimes new off-screen lines are added in the edit to explain a story point or smooth a transition. Group ADR adds the background voices of crowds and rooms, including walla, the indistinct murmur of a crowd.

ADR is valuable, but it has limits. Matching the energy, timing, and mouth movement of a performance given weeks or months earlier is difficult, and audiences can often sense when dialogue does not quite belong to the space on screen. It also requires scheduling actors again, which can be hard once they have moved on to other work. For these reasons, most sound teams treat clean production audio as the first priority and ADR as a tool for what cannot be saved.

ADR typically happens during post-production, after the rough cut has settled enough that the team knows which lines need work. For writers, it is a reminder that a scene set somewhere loud may sound very different in the finished film from how it reads on the page.