Advances in
Advances in
Digital Television
& Broadcast Technology
& Broadcast Technology
Prof. Dr. Avni Morgül
Boğaziçi University
Electrical-Electronic Engineering Department
Contents
Brief History of Television
Television Fundamentals
Colour Television
Digital TV Fundamentals
Video Compression Techniques
Audio Compression Techniques
Digital Modulation
Digital Video Broadcasting, DVB
Digital TV Receiving Systems
Recent advances
Conclusion
APCC'2003 Avni Morgul 2
Why Digital?
More reliable
Less susceptible to noise and interference
Not distorted during transmission and copying
(First copy is identical to the 100’th copy)
Digital systems can be duplicated exactly
Signal quality is controllable
Quality may be increased by increasing bits/symbol & bitrate
TV systems are merging to computer systems
(MULTIMEDIA)
Everything is going to be digital
Digital Circuits are becoming cheaper
Easy to interface with other systems
Digital signal processing techniques are advancing rapidly
Suitable for VLSI
APCC'2003 Avni Morgul 3
What is already digital?
CD (Compact Disc)
DVD (Digital Versatile [Video] Disc)
VCD (Video CD)
DAT (Digital Audio Tape)
Measuring instruments
What is going to be digital soon?
❖ TV Broadcast (DVB)
❖ TV Camera
❖ Audio/Video Recorders
❖ TV Receivers
❖ Radio Broadcast
❖ Radio / TV Receivers
APCC'2003 Avni Morgul 4
Broadcasting
TV & Radio Broadcast
Terrestrial
Mostly Analog
U.S.A., China and most of the countries has started terrestrial
digital TV broadcast
U.S.A. Going to convert all digital before the year 2010
Cable
Most cable operators started digital in parallel with analog
Satellite
Has started in 1994, there are still analog TV but digital is
dominating now
APCC'2003 Avni Morgul 5
Generation of Digital TV signals
Step 1: Analog-to-Digital Conversion
A/D SAMPLING QUANTIZATION CODING
1.0V 1.0V 7
6
amplitude
5
steps
0.5V 4
0.5V 3
2
time 1
0V 0V 0
0 1 2 3 4 5 (ms) 0 1 2 3 4 5 (ms)
0 1 2 3 4 5 (ms)
analog signal sampled signal quantized signal
Voltage (V) 0 0,143 0,286 0,429 0,571 0,714 0,857 1,00
step 0 1 2 3 4 5 6 7
code 000 001 010 011 100 101 110 111
1 encoded signal
digital signal
0
APCC'2003 Avni Morgul 6
Digitizing Video Signal
FRAME
Sampling rate PIXEL
MACROBLOK
fs > 2fmax (Nyquist limit)
fs ≈ 3fmax (Preferred)
Bits/Sample
3x8=24 b/sample (colour video)
Data Rate
Standard TV (PAL,SECAM): rn≈ 300Mb/s
fmax= 5MHz, fs= 13.5 Ms/s, rn = 13.5x24=324Mb/s
HDTV: rn > 1Gb/s
fmax= 30MHz, fs> 60 Ms/s, rn > 1.4Gb/s
Such huge bandwidths are not available!
Transmission of such data is only possible after at least
50 times of Compression!
MPEG-2 compresses STV data to 4..8Mb/s
APCC'2003 Avni Morgul 7
Video Compression Standards
JPEG For still pictures
CCITT-H261 Very low resolution
MPEG-1 Low resolution moving pictures
MPEG-2 High resolution moving pictures
MPEG-4 Interactive Video, Multimedia
MPEG-7 3-D Picture & Sound, Parametric search,
Multimedia
Error Correction is necessary!
Error Correction is necessary!
APCC'2003 Avni Morgul 8
Present Digital TV
Provides;
4 to 10 digital (SDTV) channels in 1-analog channel space
Easier and more reliable scrambling
Easier video-on-demand and Pay TV services
To the Service Provider
Same picture quality with analog (sometimes worst)
CD quality sound
2 to 10 times more money to pay for the equipment!
To the Customer
Not a fair deal!
APCC'2003 Avni Morgul 9
Video Data Compression
Based on;
Removing spatial redundancies (intra frame)
By using the transformations
Removing temporal redundancies (inter frame)
By not sending the unchanged parts of frames
Human vision system’s response
More resolution for Luminance;
Less resolution for Chrominance;
APCC'2003 Avni Morgul 10
Removing spatial redundancies (Intraframe)
APCC'2003 Avni Morgul 11
Removing temporal redundancies (Interframe)
Difference
APCC'2003 Avni Morgul 12
Human vision system’s response
+ =
More resolution for Luminance; more pixels
and more bits/pixel
Less resolution for Chrominance; less pixels
and less bits/pixel are required.
APCC'2003 Avni Morgul 13
Human vision system’s response
High resolution
is not required
for moving
sections of the
picture
APCC'2003 Avni Morgul 14
Intraframe Compression
Source Coding by using DCT (Discrete Cosine
Transform)
Based on
Converting the image to Spatial Frequency components
Assigning more bits to low-frequency components (large smooth
areas) and less bits to high-frequency components (since human
eye do not resolve the luminance levels on the fine details of the
picture)
The picture is divided into 8x8 pixel Macroblocks
The DCT is applied to each block
c( u )c( v ) 7 7 2m + 1 2n + 1
F ( u ,v ) =
4
∑∑ f ( m , n ) cos(
16
u π ) cos(
16
vπ )
m = 0n = 0
f(m,n): luminance of the pixel at coordinates m,n= 0,1,...7
f(m,n): luminance of the pixel at coordinates m,n= 0,1,...7
F(u,v): DCT coefficient of 2-D frequency u,v= 0,1,...7
F(u,v): DCT coefficient of 2-D frequency u,v= 0,1,...7
c(0)= 0.707; c(k)= 1 k=1,2,...7
c(0)= 0.707; c(k)= 1 k=1,2,...7
APCC'2003 Avni Morgul 15
Intraframe Compression (cont.)
In the DCT matrix the first component, F(0,0) , corresponds to
the DC component or, the average gray level of the complete
macroblock
The last component, F(7,7) , corresponds to the highest
spatial frequency or finest details of the picture.
APCC'2003 Avni Morgul 16
Intraframe Compression (cont.)
The DCT matrix components
are weighted by dividing each
component with a different JPEG weighting matrix
JPEG weighting matrix
number (weighting matrix)
8 16 19 22 26 27 29 34
The most important component,
16 16 22 24 27 29 34 37
F(1,1)
Corresponds to the DC or average 19 22 26 27 29 34 34 38
grey level 22 22 26 27 29 34 37 40
Divided by the smallest number,8,
generating the highest number of 22 26 27 29 32 35 40 48
significant digits. 26 27 29 32 35 40 48 58
Transmitted with max. number of
bits (or encoded by max. 26 27 29 34 38 46 56 69
quantization levels) 27 29 35 38 46 56 69 83
APCC'2003 Avni Morgul 17
Minimizing the Data
8-bit input matrix DCT matrix Trancated matrix
255 255 255 255 0 0 127 127 987 275 58 -94 32 56 -24 18 123 17 3 -4 1 2 0 0
255 255 255 255 0 0 127 127 247 273 98 -257 -50 156 -61 -153 15 17 4 -10 -1 5 -1 -4
255 255 255 255 0 0 127 127 17 40 154 -139 52 155 0 73 0 1 5 -5 1 4 0 1
255 255 255 255 0 0 127 127 -60 -106 -190 233 -27 -234 -10 -22 -2 -4 -7 8 0 -6 0 0
0 0 0 0 255 255 0 0 -96 -55 24 -23 -32 50 59 -2 -4 -2 0 0 0 1 0 0
0 255 0 0 255 255 0 0 161 123 73 -112 97 118 -48 40 6 4 2 -3 2 2 0 0
255 0 127 127 255 0 127 127 -41 5 0 14 -125 -105 -26 -86 -1 0 0 0 -3 0 0 0
127 0 127 0 0 0 127 127 -56 -94 -65 80 88 24 58 78 -2 -3 -1 2 0 0 0 0
250 244 248 264 7 36 91 131 253 243 241 264 25 18 93 134
Weighted matrix
123 17 3 -4 1 2 0 0
Inverse DCT
15 17 4 -10 -1 5 -1 -4 259 231 257 247 3 -14 127 118 244 249 264 244 -29 21 124 110
0 1 5 -5 1 4 0 1 Inverse DCT 241 279 247 244 -32 31 120 138 268 235 258 252 -22 9 127 140
-2 -4 -7 8 0 -6 0 0 267 217 266 239 33 23 98 126 249 252 249 227 51 26 76 139
-4 -2 0 0 0 1 1 0 25 36 -22 21 249 220 22 -1 10 54 -17 21 223 233 49 -22
6 4 2 -3 2 2 0 0 36 202 58 2 256 230 11 15 82 136 57 30 273 193 12 26
-1 0
0 0 00 -3 -2 0 -1 220 43 111 120 206 43 118 124 174 108 119 76 199 94 86 130
-2 -3 -1 2 1 0 0 0 103 7 113 7 6 7 133 118 121 -19 107 29 7 -18 153 112
8x8 pixel input Constructed Constructed
image image image (tranc.)
APCC'2003 Avni Morgul 18
Motion Estimation (interframe compr.)
F1 The consecutive frames of a moving picture are
almost the same since any object can not
change considerably, in 40ms (frame duration)
F2 It is not necessary to send any information for
stationary regions.
F3
Only the difference
between the F2-F3
F4 consecutive frames
should be transmitted
F5
APCC'2003 Avni Morgul 19
Motion Estimation
The new place
studied of the block
block
motion
vector
The old
place of the
block Difference between
the 1st and 2nd
1st & 2nd frames
1st frame frames
Small fit
Max. fit
Difference
between the 2nd
Predicted No fit and predicted
frame frames
2nd frame
It is enough to transmit the motion vectors and the difference between the
predicted (motion compensated) frame and next frame.
APCC'2003 Avni Morgul 20
Motion Compensation
Picture Frame
Picture Frame Motion Vectors
Motion Vectors
Difference
Difference Difference
Difference
after Motion
after Motion
Compensation
Compensation
APCC'2003 Avni Morgul 21
Channel coding
Further bitrate reduction is possible by using the VLC (Variable
length coding) before transmission.
Most commonly used coding is Huffmann coding.
Input code 000 010 110 100 111 001 101 011
Probability [%] 40 20 14 10 06 05 03 02
Output code 0 111 101 100 1100 11011 110101 110100
Input bit rate = 3 bit/symbol
Input bit rate = 3 bit/symbol
Output bit rate = 1x0.4+3x(0.2+0.14+0.1)+4x0.06+5x0.05+6x(0.03+0.02)
Output bit rate = 1x0.4+3x(0.2+0.14+0.1)+4x0.06+5x0.05+6x(0.03+0.02)
Output bit rate = 2.43 bit/symbol
Output bit rate = 2.43 bit/symbol
APCC'2003 Avni Morgul 22
Video Compression standards
JPEG Compression for Still pictures
PCM DC
Diff.
analog VIDEO
Encoder
VIDEO
A/D DCT Q VLC
Input
Zig-zag output
Encoder
input offset AC
image Q-table
Zig-zag
scanning
255 255 255 255 0 0 127 127 987 275 58 -94 32 56 -24 18 123 17 3 - 4 1 2 0 0
255 255 255 255 0 0 127 127 247 273 98 -257 -50 156 -61 -153 15 17 4 -10 - 1 5 - 1 - 4
255 255 255 255 0 0 127 127 17 40 154 -139 52 155 0 73 0 1 5 -5 1 4 0 1
255 255 255 255 0 0 127 127 -60 -106 -190 233 -27 -234 -10 -22 -2 -4 -7 8 0 -6 0 0
0 0 0 0 255 255 0 0 -96 -55 24 -23 -32 50 59 -2 -4 -2 0 0 0 1 1 0
0 255 0 0 255 255 0 0 161 123 73 -112 97 118 -48 40 6 4 2 -3 2 2 0 0
255 0 127 127 255 0 127 127 -41 5 0 14 -125 -105 -26 -86 -1 0 0 0 -3 -2 0 -1
127 0 127 0 0 0 127 127 -56 -94 -65 80 88 24 58 78 -2 -3 -1 2 1 0 0 0
input matrix DCT matrix
APCC'2003 Avni Morgul 23
MPEG Encoders
selector Quantization factor
PCM
VIDEO
- VLC Buffer
DCT Q memory
Input
Q-1
mod
estimated
picture
selector Side Info
-1 Encoder
DCT
0 + MPEG
motion
F. Error
vector Correction
selector
output
Filter Motion frame
frame
compans. memory
memory
Motion
estimation
APCC'2003 Avni Morgul 24
MPEG Decoders
MPEG Error Buffer
Input Correction memory VLD
-1
Q
Side Info -1
Decoder DCT
0
+
Filter Motion
compans.
VIDEO
frame
frame
memory
memory
output
APCC'2003 Avni Morgul 25
MPEG1
Pixel-per-line: 720
Lines-per-frame: 576
Frames-per-second: 30
Macroblock-per-frame: 396
Macroblock-per-second: 9900
Max. bitrate: 1.86Mb/s
Buffer memory size: 376 832 bit
APCC'2003 Avni Morgul 26
MPEG1
Forward estimation Forward estimation
At least one I-Frame must
be used for every 132
frames
I B B B P B B B P B
interpolation interpolation
0 1 2 3 4 5 6 7 8
Group of Pictures, GOP Slice
Slice
Block MacroBlock Slice
×
8×8
×
8×8 ×
8×8
×
8×8 ×
8×8
×
8×8 ×
8×8
×
8×8 ×
8×8
×
8×8 ×
8×8
×
8×8
YY 4×4××
4×4 ×
4×4
×
4×4 YY YY 4×4××
4×4 ×
4×4
×
4×4 YY YY 4×4××
4×4 ×
4×4
×
4×4 YY
Cb
Cb Cr
Cr Cb
Cb Cr
Cr Cb
Cb Cr
Cr
•••
×
4×4
×
4×4 ×
4×4 8×8
× ×
4×4 8×8
× ×
4×4
×
4×4 ×
4×4 8×8
× ×
4×4 8×8
× ×
4×4
×
4×4 ×
4×4 8×8
× ×
4×4 8×8
×
× 8 Cr
8×8 Cr
8×× Cb
Cb YY × 8 Cr
8×8 Cr
8×× Cb
Cb YY × 8 Cr
8×8 Cr
8×× Cb
Cb YY
Y
Y Y
Y Y
Y
APCC'2003 Avni Morgul 27
MPEG-2
Basic properties
Max. bitrate=20MB/s (HDTV)
Interlaced and progressive scanning
Different sampling choices
Scalable variable bitrate
Advanced quantization and coding algorithms
Profiles
Simple Profile
Main Profile (Standard TV)
SNR scalable Profile
Spatially Scalable Profile
4;2;0 4;2;2 4;4;4
High Profile (HDTV)
Levels
High Level
Main Level
Low level 4Y, 1Cr, 1Cb 4Y, 2Cr, 2Cb 4Y, 4Cr, 4Cb
Sampling luminance chrominance
4;2;0 - 4;2;2 - 4;4;4 (HDTV)
APCC'2003 Avni Morgul 28
Levels & Profiles
Level Sample/line line/frame Frame/sec. Max. bitrate
Low 352 288 30 4Mb/s
Main 720 576 30 15Mb/s
High 1440 1440 1152 60 80Mb/s
High 1920 1152 60 100Mb/s
Profile algorithms sampling
High Profile SNR and Spatially Scaled 3 layers 4:2:2
Spatially Scaled SNR and Spatially Scaled 2 layers 4:0:0
SNR Scaled SNR Scaled 2 layers 4:2:0
Main Profile No scaling , interlaced scan, B-type frame 4:2:0
prediction mode
Simple Profile Same as the Main profile except B-type frame 4:2:0
prediction mode
APCC'2003 Avni Morgul 29
Digital Video Picture Standards
Low Resolution Standards
SIF (Source Independent Format)
Luminance → 360×288 pixel (625-line system) or 360×240 (525-line system)
Frame rate → 25 Hz (625-line system) or 29.97 Hz (525-line system)
CIF(Common Intermediate Format)
360×288 pixel and 29.97Hz (common for 625 and 525-line systems)
QCIF (Quarter CIF)
180×144 pixel and 15 or 7.5 Hz )
Computer Monitor Standards
VGA (Video Graphic Adapter)
640x480, 31kHz/60...70Hz)
SVGA (Super VGA)
800X600 or higher, 30...65 kHz/50...120 Hz)
APCC'2003 Avni Morgul 30
MPEG4
MPEG4 is accepted in 1999. It is an easy access, adaptive,
interactive, audio and video compression standard with high
compression. Suitable for multimedia.
Basic advances:
Content based access
Tools for multimedia
Suitable coding for simultaneous data transmission
Content based scaling
Suitable coding for natural, artificial and mixed data
More efficient coding and compression
Very low bit rate coding for motion pictures
Robustness against noise and bit errors
Data rate: 5kb/s to 10Mb/s
APCC'2003 Avni Morgul 31
MPEG4 Structure
Profile-1 Syntax
Profile-2
Algorithm-1 Profile-4
Algorithm-1
Tool1 Algorithm-2 Algorithm-1
Tool2Tool1 Algorithm-2
Tool1 5Tool2 Tool1 Algorithm-2
Tool Algorithm-5
Tool5 Tool2
Algorithm-5
Tool2Tool1 Algorithm-8 Algorithm-5
Algoritma4
Tool1 5Tool2 Tool1 5
Tool Tool
Tool Algorithm-7
Tool2Tool1 5 Tool2 Algoritma4
Tool1 3Tool2 Tool1 5 Algorithm-9
Tool Tool Algoritma4
Tool2Tool1 5 Tool2
Tool
Tool7Tool2 Tool1 5
Tool
Tool5 Tool2
Tool4
APCC'2003 Avni Morgul 32
MPEG4 Structure
Sprite
Sprite
(a) (b)
Background Video Object Plane
Video Object Plane
Background
Combined
Combined
Picture
Picture (c)
APCC'2003 Avni Morgul 33
MPEG4 Hierarchy
Very Low Bitrate Video, VLBV Layer
5-64 kbit/s
Starting from a few pixels to 352x288 pixels (CIF) Frame
rate: 0 (still picture) to 15 Hz
Very high protection
High Bitrate Video, HBV Layer
Added to VLBV layer to increase the resolution
4Mb/s
APCC'2003 Avni Morgul 34
MPEG7
MPEG7 is not a compression standard, it is a Multimedia
Content Description Interface, consisting
Descriptors
Description Schemes
Description Definition Language, DDL
Description
Schemes Descriptor
Analysis MPEG-7 Application
(Description Rules (Search Engine)
Definitions)
APCC'2003 Avni Morgul 35
AUDIO
COMPRESSION
Digital Sound Compression
Old Techniques :
Instantaneous Companding
14bit linear PCM > 11 bit compressed PCM
NICAM (Near Instantaneous Companded Multiplex,
ITU-R rec.660)
32kHz,14bit linear PCM > 10 bit compressed PCM, 728kb/s
Used in analog terrestrial TV broadcast
New Techniques are based on :
Perception Coding
Frequency Domain Coding
Window Switching
Dynamic Bit Allocation
APCC'2003 Avni Morgul 37
Digital Sound Compression
Masking Effect & Perceptual
Coding
SOUND
Qualitative distortion is not important, dB LEVEL
Masking
Sound
if the difference between the original Hearing
Threshold
Masking
Threshold
and reproduction is not perceptible by
human hearing system!
High level sound masks the Masked
Sounds
neighbouring week signals. Quantization
Noise
If a signal is below the masking
threshold it is not encoded! Frequency
Frequency Domain Coding
Different sampling rate (decimation) for different frequency regions
1. Sub-band Coding, SBC
2. Transform Coding, TC
3. Hybrid Coding
APCC'2003 Avni Morgul 38
Digital Sound Compression
Window Switching Original signal
Long blocks generate long pre-
echo at the silent regions
Shorter blocks require higher bit
rate due to the overhead bits 1024 sample block
A compromise and efficient coding Pre-echo
is possible by using adaptively
changing the block size
No pre-echo
256 sample block
APCC'2003 Avni Morgul 39
Digital Sound Compression
Sound pressure
Dynamic Bit Allocation 60
40
Less bits allocated in higher
[dB]
bands 20
0
No bits assigned for masked
signals if the signal to
threshold [dB]
60
threshold ratio is smaller than
Masking
40
zero 20
20 bits/sample are reduced to 0
average 2 bits/sample (10-
Signal-to-threshold
40
times compression) 20
ratio [dB]
0
-20
-40
-60
8
Compressed
[bits/sample]
signal
4
0
15
17
19
23
25
27
10
13
21
29
1
3
5
7
9
Sub-band Number
APCC'2003 Avni Morgul 40
ISO-MPEG1 Audio Coding
CD Quality sound
Output data rate:
32, 44.1 and 48 kHz sampling rates
320kb/s for mono
448, 384 & 320 kb/s for levels I, II & III
Dynamic range = 120dB !
Level-III
Switchable hybrid filter bank,
Advanced pre-echo cancellation,
Non-uniform quantization,
Entropy coding,
Elastic buffer
Variable bitrate etc.. is added
APCC'2003 Avni Morgul 41
MPEG-2 and Dolby-AC3, 5.1 Surround Sound
L C R
SW
Center
Left Right
Subwoofer
RS
LS
Surround (Left) Surround (Right)
APCC'2003 Avni Morgul 42
5.1 Surround Encoder
For Level-I, Level-II and 5.1 Compatibility
For Level-I, Level-II and 5.1 Compatibility
1
L0 =
L0 = (( L+
L+ 2C +
C+ 2LS ))
LS
1+ 2
1
R0 =
R0 = ((R+ 2 C +
R+ C+ 2 RS ))
RS
1+ 2
T1=L0
L MPEG-1
T2=R0
encoder
Multiplexer
C
(MUX)
Matrix
R T3
LS T4 MPEG-2
RS Extension
T5
Encoder
APCC'2003 Avni Morgul 43
Broadcasting
TV & Radio Broadcast
Terrestrial
U.S.A. and most of the European and Asian countries has started
terrestrial digital TV broadcast
U.S.A. Going to convert all digital before the year 2010
Probably all countries will follow
Cable
Most cable operators preferred digital
Satellite
Digital is dominating now
Few analog broadcast exist. Being converted to digital.
APCC'2003 Avni Morgul 45
Digital Broadcast Standards
Video (ISO/IEC 1318-2, ITU-R601)
All use MPEG-2
Main Profile, Main Level for standard TV
High profile, Main level for HDTV
Modulations
Satellite : QPSK (Quadrature Phase Shift Keying) (DVB-S)
Cable : QAM (Quadrature Amplitude Modulation) (DVB-C)
Terrestrial
COFDM (Coded Orthogonal Frequency Division Multiplex) in most
countries (DVB-T)
8-level VSB (Vestigial Sideband) in U.S.A. & Canada
Sound (ISO/IEC 1318-3 )
MPEG-2 in Europe A golden opportunity
Dolby AC-3 in U.S.A to unify the global standards
missed again !
APCC'2003 Avni Morgul 46
Modulation Techniques
All countries use QPSK for satellite and QAM for
cable broadcast
DVB-T (COFDM) has been selected for use in
China, Europe, India, Latin America and South East
Asia. USA and Canada have chosen ATSC (8VSB).
South Korean Tests showed that DVB-T COFDM is
10% and 20% superior to the ATSC (8VSB) system
at stationary sites and even further ahead in mobile
APCC'2003 Avni Morgul 47
Transmitting Bitstream
TV Progr. 1
MPEG-2 V1
Video Enc.
Low Carrier Digital
MPEG-2 A1
Priority Generation Modulation
Audio Enc.
(Program&Transport)
Data (Payload)
Multiplexer
Frame
TV Progr. 2 Energy Outer Inter- Inner Adaptation
Dispersal Coder leaver Coder
MPEG-2 V2
Video Enc. Mapper
Inter-
MPEG-2 A2
leaver
Audio Enc.
Energy Outer Inter- Inner
Dispersal Coder leaver Coder
An High
Priority
Data
APCC'2003 Avni Morgul 48
DVB Hierarchy
Baseband Different video formats and PCM
layer frame rates Bit stream
Motion Luminance &
Compres- Header vectors
chrominance DCT MPEG-2
sion layer coefficients
Bit stream
Variable length codes
Transport Video MPEG-2
Packet Packet Audio Auxiliary
layer header packet header packet data Packets
Trans- Modulated
mission Different modulation and
signal
layer transmission standards
APCC'2003 Avni Morgul 49
PES: Packetized Elementary Stream
PES-1 PES-2
184-byte 184-byte 122-byte 184-byte
PES
Transport
Empty Empty Empty
packets
TP1 TP2 TP3 TP4 TP5 TP6 TP7
188-byte Transport Packet Header Payload (video, audio, etc.)
PES Header Stuffing bits
APCC'2003 Avni Morgul 50
MPEG Transport stream
video data audio1 video video audio2 data video video data audio1 …..
188-byte Transport Packet
alignment bits data bits
184-byte payload
4-byte Variable video
Transport packet alignment header
header (optional)
APCC'2003 Avni Morgul 51
Multiplexed Program Packet
PID=2
Video-1
PID=3 Progr. transport stream 1
Audio-1 System level multiplexed
PID=4 Progr. transport stream 2 data stream
Audio-2
(Transport Stream)
Progr. transport stream 3
Data-k PID=n
Progr. transport stream 4
CAT PID=1
PID=n+1
ESM (PMT) PID=0
PSM(PAT)
PID
PID
PID
PID
PID
PID
PID
PAT PMT Video1 Video2 audio1 Video2 data1
ESM: Elementary Stream Map, PMT: Program Map Table,
PSM: Program Stream Map, PAT: Program Association (Allocation ) Table CAT:
Conditional Access Table,
APCC'2003 Avni Morgul 52
De-multiplexing DVB
PID=1
Video-1
System level PID=2
Audio-1
multiplexed data
stream PID=n
(Transport Stream)
PID number
of the PMT
PID numbers
PID=0
packet
Unused
Packets
Extract the packet
number of the PMT Extract the PID
number of program
components
ESM: Elementary Stream Map, PMT: Program Map Table,
PSM: Program Stream Map, PAT: Program Association (Allocation ) Table CAT:
Conditional Access Table,
APCC'2003 Avni Morgul 53
Scrambling & Conditional Access
Scrambling & Conditional Access is used in
Pay-TV
Video-on-demand
Pay-per-view applications
The scrambling method and the necessary
information must be transmitted in the PMT
(Program Map table) and CAT (Conditional Access
(
Table).
Standard also defines a Common Scrambling
Algorithm, (CSA) .
A common interface (CI) may be used by all the
broadcast companies if CSA is used.
APCC'2003 Avni Morgul 54
Scrambling & Conditional Access
DVB standard advices two methodes
Simulcrypt system: Common scrambling algorithm
different Conditional Access
Multicrypt system: All functions are implemented in a
Common Interface, (CI), a PCMCA type exchangeable
card. Different companies may use same CI and
different Smart Cards or it is also possible to use
different CI.
APCC'2003 Avni Morgul 55
Common Interface
Two type of CI messages are generated and transmitted for de-
scrambling
ECM: Entitlement Control Messages. Transmitted every 2-sec.
EMM: Entitlement Management Messages. Transmitted every 10-sec.
The broadcast data are scrambled by using a Control Word. Two
Entitlement signals are generated by using Service & User Keys
and also broadcasted.
Service Key: Used for selecting different groups of subscribers
User Key: Used for each subscriber to scramble the Service Key
User Key
User Key Service Key
Service Key
SCRAMBLING
SCRAMBLING ECM
ECM
Control Word
Control Word ECM = f (Control Word, Service Key)
ECM = f (Control Word, Service Key) EMM
EMM
EMM = f (Service Key, User Key)
EMM = f (Service Key, User Key)
APCC'2003 Avni Morgul 56
De-Scrambling
The end-user only
knows the User Word
on his smart card. Control Word
Control Word
Control Word
The Common Interface ECM
ECM De-scrambling
De-scrambling
generates the Control Licence
Licence
Word by the help of Control
Control Service Word
user’s Smart Card Information
Information
Service Word
Service Word
EMM
EMM De-scrambling
De-scrambling
User Word
(Smart Card)
APCC'2003 Avni Morgul 57
De-Scrambling procedure
Program
Program Map
Association
table PMT
table PAT
Prog-3 Prog-3
2 4
4
4 4
3
1
PID 0 Video3 PID M Audio3 PID 1 Video3 EMM-1 EMM-2 ECM-3
5
6
Conditional Access 7
CA-1st system
table CAT EMM-1 reference
CA-2nd system
EMM-2 reference
There are other tricks which are kept secret by the companies but there is no
unbreakable code.
Several spectacular pay-tv collapses, due to endemic piracy and
comprehensive smartcard swapout programmes in many countries
APCC'2003 Avni Morgul 58
Digital TV
Receiving Systems
Digital TV Receiving Systems
Terrestial
Set -Top - Box
Satellite
Cable
Analog TV Receiver
SET
APCC'2003 Avni Morgul 60
The Set-Top-Box
Smart Card
(optional) Smart Conditional Baseband
Card Access DRAM Digital Video Baseband
Reader (optional) Analog Video
(Encoded)
Modulated
MPEG Video Video
Digital RF Front OSD Encoder
Demultiplexer
A/V DACs
End
Transport
Decoder PAL- NTSC Baseband
Analog Video
MPEG (component)
Digital
ROM A/V Data
Audio
AC-3
DAC Baseband
Decoder
Analog Audio
RS232 Micro (optional)
Controller RF
Baseband
Data Digital Audio Mod. Modulated
Comm. Power Analog RF
Modem Supply
APCC'2003 Avni Morgul 61
The Front End
Terrestrial
Ant.
Terrestrial COFDM
A/D Demod. FEC
Tuner
Satellite MPEG
SELECTOR
Ant. BITSTREAM
Satellite 2x QPSK
Tuner A/D Demod. FEC
Cable 2x QAM
Tuner A/D. Demod. FEC
Cable
Service
APCC'2003 Avni Morgul 62
Decoder
DRAM DRAM
4Mbits 16Mbits
EXT. MPEG
BITSTREAM
MPEG-2 OSD PAL/NTSC
Selector Video Decoder Encoder
Front End MPEG
Transport MPEG-2 Video
Demultiplexer Audio Decoder DACs
Smart Conditional
card Access
Dolby AC-3 Audio
Sync. Audio Decoder DACs
32-bit
Cache System CPU
Comm. 8-bit Flash ROM
Control CPU
Modem Remote Control
I2C Control Keys
APCC'2003 Avni Morgul 63
1st Generation: 2Chips+CPU+Periferals
DRAM SDRAM
Chip 1 Chip 2
4Mbits 16Mbits
MPEG-2 OSD PAL/NTSC
Selector
Video Decoder Graphics Encoder
MPEG
Transport MPEG-2 Video
Demultiplexer Audio Decoder DACs
Conditional
Access
Dolby AC-3 Audio
Audio Decoder DACs
Modem 32- bit
System & Chip 3
Cache
Control CPU IR
Sync. Remote Control
VXO Flash ROM
Clock Gen. Control Keys
APCC'2003 Avni Morgul 64
2nd Generation: 2Chips +
Chip 2
DRAM SDRAM
Chip 1
4Mbits 16Mbits
MPEG-2 OSD PAL/NTSC
Selector
Video Decoder Graphics Encoder
MPEG
Transport MPEG-2 Video
Demultiplexer Audio Decoder DACs
Conditional
Access
Dolby AC-3 Audio
Audio Decoder DACs
Modem 32- bit
System &
Cache
Control CPU IR
Sync. Remote Control
VXO Flash ROM
Clock Gen. Control Keys
APCC'2003 Avni Morgul 65
3rd Generation: Single Chip +
SDRAM SDRAM
Chip 1
4Mbits 16Mbits
MPEG-2 OSD PAL/NTSC
Selector
Video Decoder Graphics Encoder
MPEG
Transport MPEG-2 Video
Demultiplexer Audio Decoder DACs
Conditional
Access
Dolby AC-3 Audio
Audio Decoder DACs
Modem 32- bit
System &
Cache
Control CPU IR
Sync. Remote Control
VXO Flash ROM
Clock Gen. Control Keys
I2C
APCC'2003 Avni Morgul 66
4th Generation (State of the Art):
Single Chip with advanced features & graphics
SDRAM SDRAM
Chip 1
4Mbits 16Mbits
MPEG-2 Advance PAL/NTSC
Selector
Video Decoder Graphics Encoder
MPEG
Transport MPEG-2 Video
Demultiplexer Audio Decoder DACs
Conditional
Access
Dolby AC-3 Audio
Audio Decoder DACs
Modem 64- bit
System &
Cache
Control CPU IR
Sync. Remote Control
VXO
Clock Gen. Flash ROM
Control Keys
APCC'2003 Avni Morgul 67
Advanced Features
24 Bit Colour Graphics
Blending
Still Picture & Logo
Letter Boxing
2-D, 3-D Animation
PIP (With Additional Memory & Hardware)
Pan/Zoom
Teletext
APCC'2003 Avni Morgul 68
Software
The Software in DVB receivers is “harder” than its hardware!
Application Software Must be written by the Receiver
User Applications: OSD, Control, Manufacturer (Software Houses
Graphics, Program Guides, Available)
API Partially provided by the Chip
(Application Program Interface) Manufacturer
OS Provided by the Chip
(Real Time Operating System) Manufacturer or being sold by a
Third Party
DRIVER DRIVER DRIVER DRIVER DRIVER
Provided by the Chip
Manufacturer
APCC'2003 Avni Morgul 69
Converging TV & Computer
By using new multimedia techniques
Computers may be used as TV receivers
TV receivers may be used as Internet browsers
Mobil telephones may be used for Internet and TV
reception
Therefore the next generation equipment will be
multipurpose MULTIMEDIA equipment.
The software and hardware tools are available for
this purpose
APCC'2003 Avni Morgul 71
NEW MULTIMEDIA HOME
WEB-Cam
Large screen LCD or Plasma display
WB RF
Satellite Dish
distribution
Surround
Stereo Sound
Satellite
receiver
Simultaneous Small DVD-VCD Player
TV / Internet / Camera RF or IR kitchen or
display wireless badroom TV
connection Main
Computer
Laptop Multifunction
Keyboard remote
Security camera
control
Tablet
APCC'2003 Avni Morgul 72
VGA/PAL (NTSC) Conversion
PAL(NTSC) VGA SVGA
Line Freq. 15,625kHz 31kHz 30…60kHz
(15,750kHz)
Field Freq. 50 (60)Hz 60…70Hz 50…120Hz
Scanning Interlaced Progressive Progressive
ODD FIELD: EVEN FIELD:
odd numbered lines Even numbered lines
Interlaced Scanning Progressive Scanning
APCC'2003 Avni Morgul 73
VGA-PAL (NTSC) Converter
RGB
(VGA)
Buffer RGB
Buffer D/A
A/D Converter
A/D Converter Memory D/A (PAL)
Memory
converter
converter
address C-Video
PAL
PAL
clock clock (NTSC)
(NTSC)
Control
Control encoder
Circuit encoder S-Video
sync Circuit
sync
Buffer Memory = 1 line Line converter
Buffer Memory = 1 frame Frame converter
APCC'2003 Avni Morgul 74
PAL (NTSC) – VGA Converter
C-Video
(PAL) RGB
PAL
PAL A/D
A/D Buffer
Buffer RGB
Decoder
Decoder Converter
Converter Memory
Memory D/A
D/A (VGA)
address conver
conver
ter
ter
clock clock
Control
Control
Circuit
Circuit Sync.
Sync.
It is not necessary to use this converters for digital TV
receivers (or 100Hz TV) since these TV receivers already
have a VGA input.
APCC'2003 Avni Morgul 75
Multimedia Home Platform, MHP
MHP uses a delivery technology called DSM-CC Object
Carousel (OC) to deliver applications and heterogeneous data
from multiple sources
This enables the presentation of a complete ‘broadcast file-system’
Java-based applications,
Interactive services.
home shopping, home banking,
gaming, chatting, voting
super teletext, electronic programme guides, information
e-mail.
There is a DVB-MHP standard, ensuring that broadcasters,
service providers and network operators can take full advantage
of digital TV.
APCC'2003 Avni Morgul 76
Globally Executable MHP (GEM)
A single, worldwide iTV (interactive TV) standard
European Telecom. Standards Institute as ETSI TS 102 819
V1.1.1.
A GEM application will run
unaltered on an MHP digital TV
in Finland, an OCAP (Open Cable
Applications Platform) set-top box in
New York, or any other GEM-
compliant device.”
APCC'2003 Avni Morgul 77
Advanced Digital Broadcast (ADB)
Advanced Digital Broadcast (ADB), has developed an
optimised open standard solution based on the MHP
specification.
The platform, compliant with DVB MHP 1.0.1 ETSI TS 101
812 Enhanced and Interactive broadcast profiles, MPEG2
processors.
ADB has also available a set of tools that allows applications
to be designed, developed, and implemented in a simulated
end-to-end scenario, resulting in a resident applications
compatible with the MHP standard.
These include Installation Menu, Zapper, Channel Navigation
and Multilanguage Programme Menu.
And a set of interactive applications
E@syMail, T-Commerce and Information Services.
APCC'2003 Avni Morgul 78
MCP (Multimedia Car Platform)
MCP provides a powerful
architecture for multimedia
services in the car.
Positioning and
communications services could
be combined with data and
applications received via digital
broadcast.
Extended application priority
and security handling
car security breaks media
streaming
blocking distraction of the driver
while moving
APCC'2003 Avni Morgul 79
MCP (Multimedia Car Platform)
Extended application priority and security handling
car security breaks media streaming
blocking distraction of the driver while moving
Integration of APIs for Speech; Phone, Navigation, CarData and
a car radio interface
Mobile Management Client API; Seamless integration of all
types of networks (DVB-T, DAB, GSM, GPRS, Bluetooth, in-car
networks with TCP/IP; JINI service interface
User interface supporting Internet access, cached web services,
location aware services, m-commerce and entertainment.
Clever Petrol application, alerted the driver when the fuel gauge
ran under a given limit with the driver receiving navigational
instructions to the cheapest petrol station in the area.
APCC'2003 Avni Morgul 80
DVB-X
The technology was released in January 2003. It is based on the current
DVB-T standard and for the new service scenarios where small, mobile
terminals (handheld devices) receive broadcast services in various places
(inside buildings, in cars) on the move.
Provide new business for broadcast and cellular operators, chip and
equipment manufacturers.
Broadcast operators
Reach their customers anywhere, while they are on the move,
Cellular operators
A cost efficient way to implement data broadcast type of services.
For the end user
A more inexpensive and richer content
In addition to voice, messaging, internet browsing, radio, still and video
camera, TV would complement the service.
APCC'2003 Avni Morgul 81
Conclusion
Digital TV Systems have become to a mature state now
Plenty of Hardware & Software tools are available
But there is still room to improve the specifications and
to integrate more functions in a single chip
The computer, communication and TV systems are being
unified
The trend of finding better and cheaper solutions will
never end!..
APCC'2003 Avni Morgul 82