The MPEG Data Stream - Digital Video and Audio Broadcasting Technology - page 58

The header of the PMT is followed by the program_info_loop into
which various descriptors can be inserted as required which describe pro-
gram components in more detail. It does not have to be utilized, however.
The actual program components like video, audio or teletext are identified
via the stream loop which contains the entries for the respective stream
type and the PID of the elementary stream.

PMT

PID=
0x20…0x1FFE; Table_ID=0x02;

Program_number;
Version Management;

Repetition time:
25ms …500ms Section_length

PCR_PID

Program_info_length

for i=0 i<N i++

Program info

Descriptor();

for i=0 i<N i++

Stream_type;
Reserved;
Elementary_PID;
Reserved;

Stream
Loop
(Length
calculated
from
section
length)

ES_info_length

for i=0 i<N i++

ES Info
(Length from
ES_info_length)

Descriptor();

CRC_32

Fig. 3.27. Detailed structure of the Program Map Table

It is possible to include a number of descriptors for each program com-
ponent in the ES_info_loop. There is one PMT for each program and it is
sent out every 0.5 sec. There is no text information in the PMT, either.