Demultiplexing - This is separating out data streams or individual channels of data from a single multi-channel stream. For example, video and audio streams must be demultiplexed before they are decoded. This is also true for multiplexed digital television transmissions.  Thus the set-top box or other computerized device must demultiplex the TV signal it receives before it can be watched.

Decoder

Encoder (video)

See the Interactive Television Institute.