A playlist is a list of video or audio files that can be played back on a media player either sequentially or in a shuffled order. In its most general form, an audio playlist is simply a list of songs, but sometimes a loop. The term has several specialized meanings in the realms of television broadcasting, radio broadcasting and personal computers. A playlist can also be a list of recorded titles on a digital video disk. On the Internet, a playlist can be a list of chapters in a movie serial; for example, Flash Gordon in the Planet Mongo is available on YouTube as a playlist of thirteen consecutive video chapters. The term originally came about in the early days of Top 40 radio formats when stations would devise (and, eventually, publish) a limited list of songs to be played. The term would go on to refer to the entire catalog of songs that a given radio station (of any format) would draw from. Additionally, the term was used to refer to an ordered list of songs played during a given time period. Playlists are often adjusted based on time of day, known as dayparting. Cable TV and broadcast TV news channels often use video playlists to rerun prerecorded news stories. A given news story might initially be shown live and then placed into a playlist to be shown over and over again at a later time. News channel broadcasting is a combination of live and pre-recorded programming. The prerecorded clips are usually run from a playlist. As music storage and playback using personal computers became common, the term "playlist" was adopted by various media player software programs intended to organize and control music on a PC. Such playlists may be defined, stored, and selected to run either in sequence or if a random playlist function is selected, in a random order. Playlists' uses include allowing a particular desired musical atmosphere to be created and maintained without constant user interaction or allowing a variety of different styles of music to be played, again without maintenance.