Lost media

Lost media is any media that is believed to no longer exist in any format, or for which any copies cannot be located. The term primarily encompasses visual, audio, or audiovisual media such as films, television and radio broadcasts, music,^[2] and video games.^[3][4]

Many television and radio broadcast masters, recorded onto magnetic tape, may be lost due to the industry practice of wiping. Motion picture studios also often destroyed their original nitrate film elements, as film and broadcast material was often considered ephemeral and of little historical worth after they had made their revenue. Some media considered lost may exist in studio or public archives, but may not be available due to copyright or donor restriction rules.^[5] Due to unstable nature of any format, film, tape, phonograph record, optical discs like CDs and DVDs, and digital data stored on hard drives, all naturally degrade over time, especially if not kept in correct storage conditions.

Preservation efforts attempt to avoid the loss of works; this is usually done by storing them in archives, one example being the Arctic World Archive, which has been the chosen location for the preservation of the code on public repositories on GitHub^[6] along with a wide range of data of interest to multiple companies, institutions and governments; including the Constitutions of Brazil and Norway.^[7]