Transcript Service Information (SI)

Service Information(SI)

As defined by :
ETSI
EN 300 468 V1.3.1 (1998-02)
European Standard (Telecommunications series)
Digital Video Broadcasting (DVB);
Specification for Service Information (SI) in DVB systems
Well we have adopted it !
What is it ?
Compiled by Wayne Dickson
SMIREE
MIEAust. CPEng. Member SMPTE
8 July 2015
WTD
1
Is it needed ?
Service Information(SI)
DVB Service information is an enhancement of
MPEG PSI (Program Specific Information)
 It provides extra information which the receiver
can use.
 Although MPEG PSI is all that basically
essential, as the receiver will be designed to
require DVB SI, DVB SI will also be essential.
 Hence FACTS has to study and recommend the
requirements for Australia.

STATUS
Service Information(SI)

Past


Analysis of :
–
–
Current

DVB SI
ATSC PSIP
Found DVB SI best fit to DVB
Modulation for Terrestrial, Cable
and Satellite.
ATSC PSIP is a restricted SI set to 
suit ATSC 8VSB Terrestrial and
QAM on Cable plus NTSC. It may
prove to have increased efficiency
compared to DVB SI for the ATSC
system.

FACTS SI Project Group
studying DVB SI for suitability
for Australian conditions.
Standards Australia Receiver
and Transmission working
groups developing requirements
Future

Australian study groups to
change DVB/ETSI Standards to
avoid a unique Australian
standard.
PURPOSE
Service Information(SI)

Required for :
Automatic
Tuning of receiver upon selection
Programme
EPG
API
location
(Electronic Programme Guide)
(Application Programming Interface)
CA (Conditional Access)
Structure
Service Information(SI)

Before an explanation of how the basic
requirements are provided by the DVB SI, an
understanding of the structure of DVB SI is
required.
 The
DVB SI structure has it’s derivation in MPEG
ISO/IEC 13818-1 and is defined in a set of tables.
 The primary link between DVB SI and MPEG is the“PSI”
(Program Specific Information) in MPEG and is
contained primarily in the “PAT”, “PMT” and “CAT” set
of tables
PSI and DVB SI Tables
DVB
OPTIONAL
MPEG
DVB
MANDATORY
PID=0x0000
PID=P
PID=Ox0001
PID=0X0002
PAT
NIT
PID=0x0010
OTHER
Delivery Sys.
ACTUAL
Delivery Sys.
PMT
CAT
TSDT
NIT
PID=0x0010
BAT
PID=Ox0011
SDT
ACTUAL
TS
EIT
ACTUAL
TS
PCR
TDT
PROGRAMME
CLOCK REF.
TIME AND
DATE.
PID=Ox0011
PID=0X0012
PID=0X0012
BOUQUET
INFORMATION.
SDT
PID=Ox0011
SERVICE
DESCRIPTION.
OTHER
TS
EIT
EIT
ACTUAL
TS
OTHER
TS
RST
RUNNING
STATUS.
NETWORK
INFORMATION.
TOT
TIME
OFFSET.
EVENT
INFORMATION.
ST
STUFFING
TABLE.
General

What is a program ?
–
–
–
MPEG has a definition which is different to that
normally understood.
A “programme” in broadcasting is a collection of
elements with a common time base and the same start
and stop times.
A programme in MPEG is a collection of elements
with a common time base only. That is a collection of
elementary streams with same PCR_PID and
referenced to the same program_number
General contd.
–
–
–
–
Hence a conventional Broadcaster of a TV channel or
service having one program would be composed of a
series of “broadcaster programmes” or events with the
same program_number and a common PCR_PID.
In other words the PCR time base effectively creates a
virtual channel which may be associated with a single
or multiple program_numbers.
A TV channel having multiple programs would have
multiple program_numbers with either single or
multiple PCR_PID between program streams.
NOTE : Services with different program_numbers may draw upon the same video as
with the case of multilingual srevices.
General contd.

Decoding the correct program (ie “channel”) ?
–
–

Where there are several Transport Streams
available to a decoder, in order to successfully
demultiplex a program, the decoder must be
notified of both the transport_stream_id (to find the
correct multiplex) and the program_number of the
service (to find the correct program within the
multiplex).
Note again the program here refers to the channel
not the event or actual broadcast program.
Now to the various main table purposes :
Table Functions
(MPEG)

PAT (Program Association Table)
–

PMT (Program Map Table)
–

provides the link between the transport_stream_id, the
program_number and the program_map_id (PMT).
when pointed to from the PAT, the PMT provides the
associated group of elements (video, audio etc) with the
program_number.
CAT (Conditional Access Table)
–
provides the association between CA system(s) and their
EMM (Entitlement Management Messages) streams
and any special parameters associated with them.
Table Functions
(DVB SI)

NIT (Network Information Table)
–

SDT (Service Description Table)
–

provides a grouping of Transport Streams and tuning
information such as channel frequencies and
modulation characteristics.
lists the names and other information of all the
services contained within the Transport Streams.
EIT (Event Information Table)
–
contains information about present, following and
future events.
Table Function linked to
DVB SI Purpose

Automatic Tuning of receiver upon selection
–

from the information contained in the NIT and
subsequently the PAT and the PMT the decoder tunes
automatically upon selection within some version of an
EPG.
Programme location
–
an event selected via an EPG would be indentified by
a programme stream which would be located via the
PAT and PMT associated with the selected Transport
Stream.
Table Function linked to
DVB SI Purpose

EPG (Electronic Programme Guide)
–
–
Combining primarily the EIT and the SDT, both the
time and description is provided to the viewer via some
form of EPG ranging from “vanilla EPG’s”, simple
“eye plate style” displays to full blown EPG’s, either
from Receiver manufacturers designs or downloaded
EPG’s with GUI interfaces designed by the Networks.
This information so constructed and displayed can be
used to provide a Parental Guidance lock function
through PIN number access.
Table Function linked to
DVB SI Purpose

API (Application Programming Interface)
–
some form of API must be used to allow the control by
the viewer or installer of the decoder / receiver. The API
software provides the connection between the
applications (eg. EPG) and the hardware.
–
Some API’s may employ MHEG-5 multimedia support
and Java programming language for EPG generation.
–
CA in practice is reliant upon EPG’s and the API’s.
Table Function linked to
DVB SI Purpose

CA (Conditional Access)
–
connection to the EMM is provided by the CAT.
–
the EMM allows a single decoder to view the
programme material which is scrambled via a DVB
“common scrambling algorithm” by providing the key
to the code word which is involved in the scrambling.
The code word is sent via the ECM (Entitlement
Control Message).
System with CA
Control
System
CONDITIONAL
ACCESS
Video/Audio
Data Streams
Control
Word
Generator
Subscriber
Management
System
Scrambler
ECM
Generator
ECM
Subscriber
EMM
Authorisation
System
Service
Information
SI
M
U
L
T
I
P
L
E
X
I
N
G
NETWORK
D
E
M
U
L
T
I
P
L
E
X
I
N
G
De Scrambler
ECM
Smartcard
EMM
SI
Indicative Drawing of Multiplexed Service
Showing Conditional Access and Service
Information
Control
System
To OSD,
Handset.
and Tuning
Questions
Some of many !






Does each Network have to carry each others EPG
information ie carry each others EIT and SDT ?
Is there a need to define a minimum receiver requirement
for :
– API’s ?
EPG ?
CA ? Memory ?
How will the Australian Parental Guidance fit into DVB
SI ?
What data overhead will be allowed for SI ?
How will SI be managed in the Network and in translators
?
How will time zone scenarios be managed ?
Questions
Some of many !


How will Software downloads to consumers be managed
from the individual Networks ? - eg EPG enhancements
How will a particular receiver manufacturer manage
software downloads for his sets alone ?
–
–



each manufacturer will have a unique recognition of the header of software
how is it reliably sent out ? It has been suggested that up to 20 minutes could be required where
the receiver cannot receive !
Will receivers be required, in the “standby” mode, to scan
all multiplexers and download SI (EPG in particular) and
any software (Networks and manufacturers ) ?
What will the refresh rate and overhead be required in the
multiplex for SI including CA ?
Your QUESTIONS ?