| It's called ADR (automatic dialogue replacement) There's tons of info here on gearslutz and probably in google.
Main reason is poor intelligibility of production audio.
Sometimes it's called dubbing, especially when it's done in another languange.
In contrast to regular actors, which obviously have to replace their own lines on screen, dubbing actors are highly specialized pros. We in Spain are real machos and don't use visual or audio cues. Just rehearse a couple of times and lip-sync.
Regular actors usually hate to dub themselves.
hope this helps |