Introduction
MPEG is Digital Video Compression Standard known as Moving Picture Expert Group. First standard introduced by MPEG was MPEG 1 having resolution of 352 by 240 @30 FPS. While MPEG 2 is the improved version of MPEG 1. MPEG 2 provides resolution of 720*480 and 1280*720 @60 FPS. MPEG 2 is used in DVDs.
In this article we will understand about MPEG 2 Stream Types how does it works.
MPEG 2 Stream Types
There are three types of MPEG2 streams know as
Elementary Stream
Program Stream
Transport Stream.
Elementary Stream
The ES or Elementary Stream contains either Video or Audio of a channel in MPEG2 encoder. This Elementary Stream goes into the Packetizer. This packetizer gives PES or Packetized Elementary Stream in output as shown in the figure above. The bitrate of elementary stream can be fixed and variable too.
Program Stream
The Program Stream contains only one MPEG 2 channel or program. Which have video and audio both with data. So combined output of video , audio and data for a single channel known as Program Stream. There are no errors in program stream so it gives error free delivery. The bit rate of program stream can fixed and variable. Program Streams are used in DVDs,
Transport Stream
Transport Stream can contain one or more than one MPEG2 channels in it with video , audio and data of each channel. All the channels of transport stream are multiplexed. Which enable to subscriber end device which program to watch. The Transport Stream contains fix size of packed of data 188 bytes. Errors are found in the data of transport stream. ATSC and DVB uses the transport stream.
A Transport Stream containing single program known SPTS or Single Program Transport Stream while a transport stream containing multiple programs in it known as MPTS or Multi Program Transport Stream.
Conclusion
As we have discussed above there are three types of MPEG2 streams known as Elementary Stream, Program Stream and Transport Stream. Elementary Stream contains only one video or audio while Program Stream contains one program with audio, video and data. A transport stream is multiplexed form of programs and data where program can be single or multiple..
Know More About What is Transport Stream MPTS SPTS
reference : MPEG