Movies on TV often state that they have been edited for "content", "to fit this screen", and to "run in the time allotted." Obviously, movie rights are held by the studio, so presumably they are the only ones that can approve modifications to their works (outside of fair use, which reproducing 90%+ of a movie is not). What are the guidelines for what a broadcast version of the movie is acceptable? For example, some stations speed up the end credits by 100% or more, entire scenes are cut, the left and right margins are cut off for 4:3 ratios, etc. Is there an official guideline for what is and is not allowed during "editing for TV broadcast"?
Movie studios themselves provide the edited versions. They do the overdubs of foul language, and in some instances provide alternate scenes to ensure the movie still runs close to the original length (rounded to half hours with commercials).
One of the most famous and sought-after examples is TV broadcast versions of Fast Times At Ridgemont High, which used to include 18 new or extended scenes not currently found on any official DVD release. Amy Heckerling, the Director, has said she hated the scenes so much that she will never release them, and with newer and less restrictive laws for what you can and can't show on Cable TV, the only way you can find those scenes is on a VHS tape someone may have recorded from TBS in the late 80's or early 90's.