ADR (Automated Dialogue Replacement)
Definition
The process of re-recording dialogue in a controlled studio environment to replace unusable production sound. The actor performs in sync with the original picture. Despite the name, ADR is performed manually — "Automated" refers to the original Automated Dialogue Looping (ADL) process, in which picture and guide track were looped automatically for the actor to sync against.
In Simple Terms
When dialogue from a film scene sounds bad — noisy location, wind, traffic — the actor re-records their lines in a quiet studio while watching the scene. That new audio replaces the original.
In Practice
Location dialogue recorded near a busy road is replaced via ADR, with the actor re-performing their lines in a treated studio while watching the scene on a screen.