1. Digital television systems - (DTS)
Lectures
DVB transport stream
Technical Univ. of Kosice
Faculty of Electrical Engineering and Informatics
Lˇ. Maceková, 2017

2. DVB - coding – tables of transport stream

3. Example:
Calculate the bit rate at 4:2:2 sampling scheme [ITU-T B.601], at:
a)8 bit per sample for each, Y, CR, CB sample,
b) 10 bit per sample for each, Y, CR, CB sample,
Solution: a)
luminance: 13,5 MHz x 8 bits = 108 Mbps
each color difference signals: 6,5 MHz x 8 bits x 2 = 108 Mbps
------
Together: = 216 Mbps b)
luminance: 13,5 MHz x 10 bits = 135 Mbps
each color difference signals: 6,5 MHz x 10 bits x 2 = 135 Mbps
Together: = 270 Mbps
This is the basic data rate for SDI (Serial Digital Interface) for digital component signal transmission.

4. Data Bits Reduction Methods
Why?
because of data speed requirements reduction
because of data storage volume reduction
compressing data – high effective compression methods
to 100-times decreasing of the data amount (1 to 6 Mbps per program)
compression standards (MPEG-2, MPEG-4): removing of redundancy (DPCM, DCT-transformation, prediction methods in the GOPs – Groups-of-Pictures I,P,B, VLC (Variable Length Coding)

5. In the opposite side, there are effective transmission methods developed.
Why?
- for data speed increasing
How?
using of multiple carriers system (OFDM, COFDM)
digital modulations QAM, QPSK (multistate modulation of each carrier)
error prevent and correction methods (channel coding - FEC - RS code, convolution codes, inter-bit and inter-symbol interleaving)

6. The MPEG-2 tables
Program Service Information (PSI)
Program allocation table (PAT)
always present (packets PID = 0×0000).
indication (for each program in the transport multiplex) = “interconnections” between program number (from 0 to 65535) and PID of packets which transmits the program map (Program Map Table—PMT).
Conditional access table (CAT)
It is present once at least 1 program in the multiplex has conditional access
It is transported by packets PID = 0×0001. It indicates PID of the packets of EMM (EMM is one of 2 information required for descrambling of coded program)
Program map table (PMT)
1 x PMT for each program in multiplex
PID of elementary stream (coded program and alternatively other privat information relevant to program, e.g.ECM for the descrambling)

7. Tab. Illustration of PAT
Field (PAT)
Comment
No. of bits
Table_id (00)
Always 00 for the PAT 8
Section_syntax_indicator 0
Always 1
Always 0 1
Reserved 2
Section_length
Max. value 1021 (2 MSB = 0) 12
Transport_stream_id
Stream identification (in a network) 16
Version_number
Incremented at every PAT modification 5
Current_next_indicator
1 = current PAT, 0 = next
Section_number
Number of current section (1st = 00)
Last_section_number
Number of last section (JVtot−1)
....
...
CRC_32
CRC on 32 bits 32

8. Transport stream description table (TSDT)
description of the multiplex content
PID = 0×0002 packets
Others privat tables ....
DVB-SI Table (DVB – Service Information):
- allows automatic configuration of the receiver
- allows user access to a lot of programs and services
- 4 mandatory and 3 optional ones:
Network information Table (NIT)
the frequencies and No. of channels (for receiver configuration)
PID = 0×0010
Service description table (SDT)
list of the names and parameters of other services in multiplex
PID = 0×0011.
Event information table (EIT), present/following
information about events present or incoming by actual transport multiplex
PID = 0×0012.
Time and date table (TDT)
- for the update of internal time/clock of set-top-box
- PID = 0×0014.

9. Optional tables in DVB-SI Bouquet association table (BAT)
Running status table (RST)
Time offset table (TOT)
Stuffing tables (ST)
PID hex (13 b)
Table ID hex (8b)
Repetition
Min Max
Table PSI
PAT
0000 00
25 ms
100 ms
CAT
0001 01
PMT
0020 to 1FFE 02
NIT
0010
40 to 41
10 s
Table SI
10 to 41
SDT
0011
42, 46
2 s
BAT 4A
EIT
0012
4E to 6F
RST
0013 71 -
TDT
0014 70
30 s
TOT 73 ST
0010 to 001F 72
the tables are repeated very often for quick access of the decodes to information in the case of the channel change
ETSI TR

10. RTCP-protocol (Real-time Transport Control Protocol)
Unicast
RTCP-protocol (Real-time Transport Control Protocol)
user affects the transport (the content, start, stop, interruption)
example: YouTube, Video-archive
higher demands on transport capacity/ throughput of lines routers, switchs
Multicast
RTP-protocol (Real-time Transport Protocol)
1 directional communication
the user can not affect the communication
example: IPTV
TV JOJ , 6 Mbps
6 Mbps

11. S = shift register length R = m/n = code ratio < 1
Convolution coder
e.g.: =1 =2
=1/2 =3
m = inputs number
n = outputs number
S = shift register length
R = m/n = code ratio < 1
K = (S+1). m = length of
State diagram
The generating polynomial: G1=x2+x+1=78, G2= x2+1=58, hence [7,5]8 or [111, 102]2
if ip = 0
if ip = 1
current state
next state (op) 00
00 (00)
10 (11) 01
00 (11)
10 (00) 10
01 (10)
11 (01) 11
01 (01)
11 (10)
Table of transitions between states