Introduction
The systems part of this Recommendation | International Standard addresses the combining of one or more elementary
streams of video and audio, as well as other data, into single or multiple streams which are suitable for storage or
transmission. Systems coding follows the syntactical and semantic rules imposed by this Specification and provides
information to enable synchronized decoding of decoder buffers over a wide range of retrieval or receipt conditions.
System coding shall be specified in two forms: the Transport Stream and the Program Stream. Each is optimized for a
different set of applications. Both the Transport Stream and Program Stream defined in this Recommendation |
International Standard provide coding syntax which is necessary and sufficient to synchronize the decoding and
presentation of the video and audio information, while ensuring that data buffers in the decoders do not overflow or
underflow. Information is coded in the syntax using time stamps concerning the decoding and presentation of coded
audio and visual data and time stamps concerning the delivery of the data stream itself. Both stream definitions are
packet-oriented multiplexes.
The basic multiplexing approach for single video and audio elementary streams is illustrated in Figure Intro. 1. The
video and audio data is encoded as described in ITU-T Rec. H.262 | ISO/IEC 13818-2 and ISO/IEC 13818-3. The
resulting compressed elementary streams are packetized to produce PES packets. Information needed to use PES
packets independently of either Transport Streams or Program Streams may be added when PES packets are formed.
This information is not needed and need not be added when PES packets are further combined with system level
information to form Transport Streams or Program Streams. This systems standard covers those processes to the right
of the vertical dashed line.