Enhanced Error Protection and AV Streaming in DAB

1
The DXB Project - Objectives, Concepts and
Structure Ralf Schäfer Fraunhofer
Heinrich-Hertz-Institut http//dxb.hhi.de
2
DVB-T DAB for broadcast services to handhelds

• DAB and DVB-T are both wireless data
  broadcasting systems
• DVB-T and DAB are both suitable for multimedia
  services
• DVB-H is a compatible extension of DVB-T making
  portable reception of DVB-T signals possible _at_
  reasonable power consumption
• MBMS is a 3GPP based technology for broadcast
  services in one cell
• New and most efficient coding schemes for video
  (H.264/AVC) and audio (HE- AAC, AMR-WB) are now
  available to transmit high quality multimedia
  services _at_ economical bit rates to handhelds
• DAB can be upgraded (extended DAB) in a
  similar way as DVB-H from DVB-T
• The availability of free spectrum for mobile
  broadcast services is different in different
  parts of the world, therefore DVB-H, extended
  DAB (eDAB) and MBMS will co-exist

3
The DXB concept

• DXB Harmonisation of DAB with DVB-T/DVB-H (and
  MBMS)
• - Not touching the physical layer of DAB
• - upgrading DAB -gt eDAB to make it suitable
  for data casting
• using MPEG-2 TS as common transport layer (as
  one option !!!)
• using IP as common protocol layer
  (mandatory!!!)
• using H.264/AVC and HE-AAC/WB-AMR as common
  content representation
• using the IP datacast specifications
  currently developed in DVB-CBMS or related
  specifications of 3GPP/MBMS or OMA/BCAST

4
DXB Common IP based Broadcast Infrastructure for
Mobiles
DXB
Multimedia
IPDC CBMS (MBMS, BCAST) Access to content
Data
Radio
TV
DMB
IP
eDAB
MBMS
DVB-H
MOT
DAB
UMTS
DVB
5
Current situation in DAB comparison with DVB-H
6
The Korean T-DMB System
Source Signals

• Smart and highly efficient Solution on its own
• Corresponding DAB Standards awaiting JTC
  approval
• Regular introduction foreseen in South Korea for
  July 2005
• Degree of alignment to 3G/UMTS and DVB-H is
  limited

H.264 video BSAC audio codecs
MP4-SL Packetizer
PES Packetizer
MPEG Transport Stream
Adopted from DVB-T
RS(204,188)
Interleaver
Source Frank Herrmann - WorldDAB Forum Technical
Committee Chairman
7
The DXB approach 3 options
H.264 video AAC-HE audio codecs
H.264 video AAC-HE audio codecs
H.264 video AAC-HE audio codecs
RTP
RTP
RTP
UDP
UDP
UDP
IP
IP
IP
Data groups
Multi Prot. Encaps.
Multi Prot. Encaps.
Packet layer
TS TS TS TS
MPEG TS
DAB-FEC
DVB-FEC
DVB-FEC
RS data encaps.
Further DAB subchannel processing
Further DAB subchannel processing
Further DAB subchannel processing
2) MPEG-TS multiple TS
3) MPEG-TS - single TS
1) DAB Enhanced Packet Mode
R. Schäfer The DXB Project
8
Enhanced Packet Mode vs. MPEG-TS Selection
Criteria (1)
9
Enhanced Packet Mode vs. MPEG-TS Selection
Criteria (2)
10
The DXB Project

• Working Items
• DXB system development standardisation
• Optimisation of video and audio transmission
  (e.g. statistical multiplex)
• Service and coverage aspects
• Quality of service
• Demonstrator
• Field trial
• Partners
• IRT, Siemens, Sony, T-Systems, Vodafone, FhG/HHI
• Coordination FhG/HHI
• Contact Ralf Schäfer (schaefer_at_hhi.de)

11
Current activities

• Current Working Items
• DXB system development standardisation
• Different system options under investigation
• First draft system proposal hopefully after
  July meeting
• Active participation in standardisation bodies
• - DVC-CMBS
• - WORLDDAB Allignment Task Force (meeting on
  29.6.2005)
• Optimisation of video and audio transmission
• - Prototype of statistical Multiplex is under
  development at HHI and will be demonstrated at
  IFA and IBC

12
Rate distortion curves for different video
sequences
PSNR dB
Programme 1 2 3 4 5 6

38
36
Given quality level (34 dB)
34
32
Mean bit rate
30
Bit rate variation
28
Worst case bit rate
Bit-Rate kbps
26
0
100
200
300
400
500
13
Visual quality versus bit rate
Quality
Programme 1 2 3 4 5 6

100
90
80
70
60
50
Worst case bit rate
Mean bit rate
40
Bit-Rate kbps
30
150
200
250
14
Statistical multiplex
PSNR dB
Programme 1 2 3 4 5 6

Statistical multiplex gain 33
38
36
34
32
30
28
Bit-Rate kbps
26
0
100
200
300
400
500
15
Conclusions

• There is an increased worldwide interest in
  broadcast services to handheld devices.
• Several systems (DVB-H, T-DMB, 1 segment
  ISDB-T, MediaFlo, MBMS) are under development or
  in the introduction phase.
• The Korean T-DMB system is NOT an option for
  Europe, because of the missing IP layer.
• The availability of free spectrum for mobile
  broadcast services is different in different
  parts of the world, therefore DVB-H, extended
  DAB (eDAB) and MBMS will co-exist.
• DXB is a system concept to harmonise the
  transport protocols above the physical layer and
  media formats for all three systems
• Specification work is ongoing, a decision about
  the utilisation of MPEG-TS for eDAB is pending
• First results on the benefit of using
  statistical multiplex for video coding in eDAB
  have been presented.