Multichannel television sound

Multichannel television sound, better known as MTS or (BTSC), is the method of encoding three additional channels of audio onto an NTSC-format video signal.

The first channel is the stereo difference, used to add stereophonic sound to the existing monophonic audio track. The second audio program (SAP) also is part of the standard, providing another language, a video description service like DVS, or a completely separate service like a campus radio station or weatheradio.

A third PRO (professional) channel is provided for internal use by the station, and may handle audio or data. It is normally used during news broadcasts to talk to the remote location (such as a reporter on-location), which can then talk back through the remote link to the station. Receivers for this channel may not be sold to the public.

MTS is part of the BTSC standard.