Elementary streams are the raw information component streams (such as audio and video) that are part of a program stream. MPEG system divides a multimedia source into elementary streams (ES). Elementary streams may be video, audio or data and there may be several elementary streams for each type of media (such as multiple audio channels for surround sound).

A packet elementary stream - PES - is a raw information component stream (such as audio and video) that has been converted to packet form (a sequence of packets) which is part of a program stream (such as a digital television program). This packetization process involves dividing (segmenting) a group of bits in an elementary stream and adding packet header information to the data. This packet header includes a packet identification code (PID) that uniquely identifies the packetized elementary stream from all other packetized elementary streams that are transmitted.

A program stream is a combination of elementary streams (such as video and audio) that compose a media program (such as a television program). A program stream is called single program transport stream (SPTS).

Transport Streams are the combining (multiplexing) of multiple program channels (typically digital video channels) onto a signal communication channel (such as a satellite transponder channel). A MPEG transport stream (MPEG-TS) is also called a multi-program transport stream (MPTS).