Karaoke is a form of entertainment in which an amateur singer or singers sing along with recorded music on microphone. The music is typically of a well-known song in which the voice of the original singer is absent or reduced in volume. Lyrics are usually also displayed, sometimes including color changes synchronized with the music, on music video to guide the sing-along. Karaoke has been a popular form of entertainment beginning first in Japan, then the rest of East Asia, since at least the 1980s, and has since spread to other parts of the world. Some computer programs that serve a similar purpose to the standard karaoke machine have been developed that use MIDI instrumentation to generate the accompaniment rather than a recorded track. This has the advantage of making transposition technically trivial and also shrinks the information needed to provide the accompaniment to the point where it is easy to transfer it across the Internet, even over slow connections. The standard file format used is *.KAR, which is an extension of the standard .MID MIDI disk format which includes embedded lyrics and can be played unaltered by MIDI player software. A basic karaoke machine consists of a microphone, a means of altering the pitch of the recorded music, and an audio output.