Philips 14AA3322/40B Installationsanleitung PDF herunterladen (Seite 18)

Generation of a transport stream for DVB and realisation of a HF-modulated DVB-signal

18 | P a g e

Image 9.1.3.3.1: PS structure

9.1.3.4 Transport stream (TS):

Transport stream or TS is a container of multiple multiplexed programs including audio and

video. To create a transport stream, packets of one program are multiplexed together. All the

multiplexed data streams of all the programs are then multiplexed again and combined to form

a complete data stream which is called an “MPEG-2 transport stream”. An MPEG-2 transport

stream contains the 188-byte-long transport stream packets of all programs with all their video,

audio and data signals. For each program there is one MPEG encoder which encodes all

elementary streams, generates a PES structure and then packetizes these PES packets into

transport stream packets. The transport streams of all the programs are then combined in a

multiplexed MPEG-2 data stream to form one overall transport stream. There are often up to 6,

8 or 10 or even 20 programs in one transport stream. The data rates can vary during the

transmission but the overall data rate has to remain constant. A program can contain video and

audio, only audio (audio broadcast) or only data, and the structure is thus flexible and can also

change during the transmission. To be able to determine the current structure of the transport

stream during the decoding, the transport stream also carries lists describing the structure,

called “tables”. Transport streams can be found in “.ts”, “.trp” which are direct broadcast

formats and “.mpg” formats.

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Philips 14AA3322/40B Installationsanleitung Seite 18