Philips 14AA3322/40B Guía de instalación descargar pdf (Pagina 17)

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

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optional header. From the PES packets, 184-byte-long pieces are taken and to these another 4-

byte-long header is added, making up 188-byte-long packets called “transport stream packets”

which are then multiplexed. They can be multiplexed directly in transport streams for

broadcasting or they can be saved as program streams.

Image 9.1.3.2.1: PES (from the presentation of Walter Fischer in Belgium 2008).

9.1.3.3 Program stream (PS):

The program stream or PS is a container format for multiplexing audio, video and data. Program

streams are used on DVD-Video discs and HD DVD video discs, but with some restrictions and

extensions. The filename extensions are VOB and EVO respectively. Program streams are

created by combining one or more packetized elementary streams (PES), which have a common

time base, into a single stream. It is designed for reasonably reliable media such as disks, in

contrast to MPEG transport stream which is for data transmission in which loss of data is likely.

Program streams have variable size records and minimal use of start codes which would make

over the air reception difficult, but has less overhead. Program stream coding layer allows only

one program of one or more elementary streams to be packaged into a single stream, in

contrast to transport stream, which allows multiple programs.

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Philips 14AA3322/40B Guía de instalación Pagina 17