DVB Overview
Founded in 1993 and published by the European Telecommunication Standards Institute (ETSI).
The standard are based on the ISO MPEG-2 standard, but extend this to cover system specific details to ensure a fully specified system.
The alternate system is specified by the US i.e. Advanced Television Systems committee (ATSC).
DVB standards is grouped by the transmission method employed
MPEG-2 is a set of standards for building of a single digital transport stream which can carry a dozen programs or more,
depending upon the compression used and the communication bandwidth.
MPEG-2 System Layer is called as a Program specific Information (PSI) table.
What is MPEG-2
MPEG-2 (Motion Picture Experts Group - 2) is a compression standard for digital television. MPEG-2 compression enables digital television broadcasters to transmit video streams with higher resolution and audio streams with higher quality sound while using as little bandwidth as possible.
MPEG-2 is capable of reducing the amount of bandwidth utilized by as much as 55 to 1.MPEG-2 is utilized by DVB, HDTV, and DVD.
MPEG-2 has been adopted as ISO Standard 13818-1.
PSI Tables
Program Association Table( PAT )
A root directory for the transport stream, the table provides the PID value for the
packets containing the PMT associated with each program.
PID for PAT is 0x0000.
Conditional Access Table( CAT )
This table provides the PID value for the packets containing each Entitlement Management Message( EMM ).
EMMs update the subscription options or pay-per-view rights per subscriber.
PID for PAT is 0x0001.
Program Map Table( PMT )
The PMT lists the PID values for the packets containing a program's video, audio, clock refernce and
data components. It also lists the PID value for each Entitlement Control Message( ECM ) in the
stream. ECMs enable a decoder to descramble the audio, video and data for a program.
PMT found in PMT.
Network Information Table( NIT )
This table is not defined by MPEG-2.
SI Tables
While MPEG-2 PSI tables enable the decoder to decipher the programs on a single transport stream, they do not provide enough information to support the numerous programs and services available on an entire network of transport streams. The Digital video Broadcast (DVB) standard defines a set of tables, called Service Information (SI) tables, that extend the capabilities of the MPEG-2 system layer such that a decoder can receive and decode any number of programs and services across a network of transport streams.
PSI Tables
Network Information Table( NIT )
This table shows the physical organization of the network and its characteristics.
PID for this table is 0x10.
Time and Data Table( TDT )
The TDT provides the present UTC time.
PID for this table is 0x14
Service Description Table( SDT )
This table describes the services in a network and gives the name of the service provider.
PID for this table is 0x11.
Event Information Table( EIT )
This table defines all events in the network, providing their description, start time and
duration. It is used in creation of the Electronic Program Guid( EPG ). PID for this table is 0x12.
Bouquet Association Table( BAT )
The BAT describes the services available in a given bouquet, or group of services that can be
purchased as a single product. PID for this table is 0x11.
Running Status Table( RST )
The RST updates the timing status of events when scheduling changes occur.
PID for this table is 0x13.
Timing Offset Table( TOT )
The TOT contains the UTC time and date and the local time offset.
PID for this table is 0x14.
Stuffing Table( ST )
This table invalidates the remaining sections of a table when one sections has been overwritten.
PID for this table is 0x10 to 0x14.
| Table | PID |
| Program Association Table ( PAT ) | 0x0 |
| Conditional Access Table( CAT ) | 0x1 |
| Network Information Table( NIT ) | 0x10 |
| Service Description Table( SDT ) | 0x11 |
| Running Status Table( RST ) | 0x13 |
| Time Offset Table( TOT ) | 0x14 |
| Stuffing Table ( ST ) | 0x10 to 0x14 |