DIGITAL VIDEO BROADCAST. Presented by. Mike Barnett. Jean-Baptist Blondel. Marie Rajon for. 94.581 taught by. Prof. Jun Huang in. Winter 2001 ...
DIGITAL VIDEO BROADCAST Presented by Mike Barnett Jean-Baptist Blondel Marie Rajon for 94.581 taught by Prof. Jun Huang in Winter 2001
Outline • • • • •
Introduction DVB In General Transmission Mediums The Future Conclusions
The Challenge Your company has unlimited VC (Venture Capital), and you are allowed to play with all 3 (DVBS, DVB-T, DVB-C) technologies (but one at a time). Since the president is originally from Europe, she wants your team to examines these 3 standards. Do some technical comparisons, and tell her: which to do first and which to do last.
PART ONE
WHAT IS DVB?
! European-based consortium - ≈ 300 companies - 1993 ! From analog to digital TV broadcasting… ! … but also data broadcasting services (broadband Internet) ! Over satellite, terrestrial and cable links ! New promising interactive services ! Targeted market: residential, institutional and corporate
STANDARD’S PUZZLE ET SI
IETF
DV DA
VI
C
B E E E I
DEVELOPING “DVB” STANDARDS ETSI ITU-R COMMERCIAL
TECHNICAL
STEERING
MODULE
MODULE
BOARD
ITU-T DAVIC CENELEC
“user requirements”
“specifications”
!A collection of ETSI standards: • DVB-S (satellite) • DVB-T (terrestrian) • DVB-C (cable)
Generic Model of the System (for satellite, terrestrial and cable systems)
Source
• Source coding • Multiplexing (MPEG-2)
• Satellite, • Cable, • or Terrestrial • Energy dispersal • Error-correction coding • Modulation
Source coding and multiplexing MPEG-2 Digital Signal Video Source (analog)
C N A
Compressed Digital Signal
Post Production Processing
Video Encoder
One program composed of elementary streams PES
Packetizer
Video Source (digital)
Audio Source
Post C N Production A Processing
TS Audio Encoder
Data source
Transport Multiplexer
Packetizer
Packetizer Timing Data Service Information Access Control Information Private Data
MPEG-2 Compression algorithms Forward prediction
FORMAT BEFORE
AFTER
HDTV
885 Mb/s
20-25 Mb/s
SDTV
166 Mb/s
4-8 Mb/s
Bi-directional prediction
Basic principles: • intra-image coding (redundancy within the image) • inter-image coding (redundancy between successive images) • hierarchical flow (low-level flow with medium quality complemented by high-level flow for high quality)
DVB Transmission System: MPEG-2 TS PES packet structure
DVB-S ! First digital transmission (90’s) ! Modulation Method: QPSK (Quaternary Phase Shift Keying) ! Each transponder = 38 Mbps => 4 to 8 standard definition TV channels ! Requires satellite terminal (dish) ! Return Channel via Satellite (DVB-RCS) - for SME and residential - efficient for multicast
DVB-T ! Better known as digital through aerial ! Noisy environment (multipath channel, adjacent channel, fading…) => Modulation Method: OFDM ! Less bandwidth ! Mobile reception ! ! Return Channel: on its way…
DVB-C ! More bandwidth ! Competitor: MCNS (US) ! Modulation method: QAM (Quadrature Amplitude Modulation) ! Permanently connected broadband path ! Faster, more interactive, more channels. ! Return channel: DVB-RCC
DVB- Return Channel
BROADCASTING
BROADCAST CHANNEL
DELIVERY
SET TOP BOX (STB)
BROADCAST
BROADCAST
BROADCAST
SERVICE
NETWORK
INTERFACE
PROVIDER
ADAPTER
MODULE
INTERACTIVE
FORWARD
INTERACTIVE
INTERACTION
SERVICE
NETWORK
PROVIDER
ADAPTER
PATH
INTERACTIVE
SET TOP UNIT (STU)
MEDIA
INTERFACE RETURN INTERACTION
INTERACTION
MODULE
NETWORK
PATH
INTERACTION CHANNEL
NETWORK INTERFACE UNIT (NIU)
General Comparison of DVB Systems
STANDARD
BANDWIDTH
MODULATION
(CAPABILITY)
(COMPLEXITY)
ERROR CORRECTION (SOPHISTICATION)
DVB-S
MEDIUM
MEDIUM
HIGH
DVB-T
LOW
HIGH
MEDIUM
DVB-C
HIGH
LOW
LOW
Low, Medium, High relative to each other.
PART THREE
GROWTH USERS 8 MILLION 1998 22 MILLION - 1999 233 MILLION - 2005
THE FUTURE
TY LI A U Q
S E M M UL E H T TI S O M S E P ED N P I E OR IA C BUS I TU O NI CH E C N T E I N IE E V N S CO FLEXIBILITY
RECOMMENDATIONS? FACTORS: WHERE? MOBILITY? WELL ESTABLISHED? REMOTE? INTERACTIVITY?
DIGITAL TV !Digital TV:
!New interactive services:
More TV channels
• Broadband Internet
Improved programs:
• Home shopping
• Better video and audio quality
• Distance learning
• Subtitling language
• Video Conferencing
• Different audio languages
• Smart Devices
• Different camera angles • Near video-on-demand Better navigational aids And Mobile Reception!
CONCLUSIONS - INITALLY DVB-S - EVENTUALLY DVB-C - DVB-T (SPECIAL FACTORS OR COMBINED WITH ABOVE)
