Such regulation includes determination of the width of the bands, range, licensing, types of receivers and transmitters used, and acceptable content.
Cable programs are often broadcast simultaneously with radio and television programs, but have a more limited audience. By coding signals and having a cable converter box in homes, cable also enables subscription-based channels and pay-per-view services.
A broadcasting organisation may broadcast several programs at the same time, through several channels (frequencies), for example BBC One and Two. On the other hand, two or more organisations may share a channel and each use it during a fixed part of the day. Digital radio and digital television may also transmit multiplexed programming, with several channels compressed into one ensemble.
When broadcasting is done via the Internet the term webcasting is often used. In 2004 a new phenomenon occurred when a number of technologies combined to producepodcasting. Podcasting is an asynchronous broadcast/narrowcast medium, with one of the main proponents being Adam Curry and his associates the Podshow.
Film.
'Film' encompasses motion pictures as individual projects, as well as the field in general. The name comes from the photographic film (also called filmstock), historically the primarymedium for recording and displaying motion pictures. Many other terms exist "motion pictures (or just pictures and "picture"), the silver screen, photoplays, the cinema, picture shows, flicks "and commonly movies.
Films are produced by recording people and objects with cameras, or by creating them using animation techniques and/or special effects. They comprise a series of individual frames, but when these images are shown rapidly in succession, the illusion of motion is given to the viewer. Flickering between frames is not seen due to an effect known aspersistence of vision "whereby the eye retains a visual image for a fraction of a second after the source has been removed.
