Stock footage

[Greta]

[Stock footage], also termed [archive] footage, library pictures and file footage is film or video footage either in the [public domain] or available for a set fee that can thus be put into any other film. Stock footage is of great use to filmmakers as it is generally far cheaper than actually filming a needed scene. Documentaries, as well as student films are noted for using large amounts of [stock footage].
Stock footage can also be used to integrate news footage or notable figures into a film. For instance, the Academy Award-winning film Forrest Gump used stock footage extensively, to portray the lead character meeting historic figures such as [John F. Kennedy], Richard Nixon, and John Lennon.
One of the largest producers of public domain stock footage is the United States government. All videos produced by the United States military, NASA, and other agencies are available for use as stock footage. There are a number of companies that own the copyrights to large libraries of stock footage and charge film makers a fee for using it, but they rarely demand [royalties]. Stock footage comes from a myriad of sources, including governments, other movies, and often news outlets.
Television and movies series also often use stock footage taken from previous installments. For instance, all [the Star Trek] series kept a collection of shots of starships that would appear on a regular basis, being used most of the time a ship was seen.
News programs use film footage from their archives often when more recent images are not available.