ADR (Additional Dialogue Recording) is a post-production process in which the actors come in to re-record lines to improve audio quality. If an actor mumbles their line on screen or their line can't be heard because of environmental interference, like waves and wind on the beach, we bring them in to make it more intelligible. After watching the scene, the actor attempts to recreate the performance as closely as possible. We also use ADR to record Emily's many narrations.
Photo credit: Chad Savage