Obtaining Copyright Clearances for Multimedia Works
Generally, permission must be obtained to use the appearance, voice, or personal style of an individual. Even if permission has been received from the studio–and even if the film is in the public domain–permission may need to be obtained from the performer.
Even fictional characters are often protected by copyright law, particularly if the character appears in more than one work.
If trademarks are shown, permission may be required from the companies owning those marks–they may be quite sensitive about their image.
While a particular piece of music may be in the public domain, a specific performance of that piece (for example, the London Philharmonic's rendition of Beethoven's Fifth Symphony) may well be protected.
Although not widely accepted in the United States yet, many foreign countries recognize an artist's "moral rights" to prevent modification to a work. Merely obtaining the rights from a legitimate source to use a work may not be sufficient to allow a multimedia developer to modify that work.
Even where rights are obtained to a film clip, a multimedia developer may also have to obtain permission directly from the author of an underlying or previous work (such as a script).
In general, if a work is used solely in the background–so that it is not particularly noticeable and no attention is drawn to it–permission to use it may not be required.