TheOneRing.net can confirm rumors that Ian McKellen (Gandalf) and Elijah Wood (Frodo) plus other cast members are back in New Zealand doing some ADR (Automatic Dialog Replacement) work and some pick up photography for various scenes throughout the films.
More on ADR or ‘Looping’
ADR stand for “Automated” or “Automatic” Dialog Replacement.
Dialog that cannot be salvaged from production tracks must be re-recorded in a process called looping or ADR.
Looping originally involved recording an actor who spoke lines in sync to “loops” of the image which were played over and over along with matching lengths of recording tape. ADR, though faster, is still painstaking work.
An actor watches the image repeatedly while listening to the original production track on headphones as a guide. The actor then re-performs each line to match the wording and lip movements. Actors vary in their ability to achieve sync and to recapture the emotional tone of their performance.
Marion Brando likes to loop because he doesn’t like to freeze a performance until he knows its final context. (People have said that one reason he mumbles is to make the production sound unusable so that he can make adjustments in looping.)
ADR is usually considered a necessary evil but there are moments when looping can be used not just for technical reasons but to add new character or interpretation to a shot. Just by altering a few key words or phrases an actor can change the emotional bent on a scene.