The MPEG Data Stream - Digital Video and Audio Broadcasting Technology - page 67

provided. An example of this is the pay TV provider “Premiere”. A hand-
ful of satellite or cable DVB channels are combined here to form a bouquet
of this provider's channels. The associated BAT is transmitted in all indi-
vidual channels and links this bouquet together.
In fact, however, a bouquet association table is found very rarely in a
transport stream. The broadcasters ARD and ZDF in Germany, and Pre-
miere, are broadcasting a BAT for their respective bouquet and sometimes
a BAT can be found in networks of cable network providers.
But frequently, the BAT doesn't exist at all, as already mentioned.
When it does exist, it tells by way of so-called linkage descriptors which
service of a particular service ID can be found in which transport streams.
Many providers are also transmitting an “electronic program guide”
(EPG) which has its own table in DVB, the so-called “event information
table”, or EIT for short (Fig. 3.38. and 3.39.). It contains the planned start-
ing and stopping times of all broadcasts of, e.g. one day or one week. The
structure which is possible here is very flexible and also allows any
amount of additional information to be transmitted. Unfortunately it is true
that this feature is not supported by all set-top boxes, or only inadequately
so.
EIT
Event Information Table
(PID=0x12, Table_ID=0x4E..0x6F)
Electronical Program
Guide
(EPG)
Fig. 3.38. EIT
Frequently, however, there are variations and delays in the planned
starting and stopping times of broadcasts. To be able to start and stop, e.g.
a video recorder at a given time, the relevant control information is trans-
mitted in the “Running Status Table” (RST). The RST can thus be com-
pared to the VPS (video program system) signal in the data line of an ana-
log TV signal. The RST is currently not being used in practice, or, at least,