McCann1
-
Upload
shikha-sinha -
Category
Documents
-
view
218 -
download
0
Transcript of McCann1
-
8/4/2019 McCann1
1/10
1
Data Broadcasting
Ken McCann
-
8/4/2019 McCann1
2/10
2
Application Example - Internet via satellite
ServiceProvider
SatelliteOperator
InformationProvider
User PC
DVB Card
18" dish
Leased line
The Net
Delivery of web pages
at up to 38 Mbit/s
-
8/4/2019 McCann1
3/10
3
DVB Return Channel
Return channel used for interactiveservices depends on the physical network,e.g.:
Telecom modem via PSTN & ISDN forterrestrial or satellite TV
DVB/DAVIC modem for cable TV
-
8/4/2019 McCann1
4/10
4
DVB Data Broadcasting
DVB Data Broadcasting standard, EN 301 192,provides a set of network-independentprotocols optimised to different applications:
data piping data streaming
multiprotocol encapsulation
data carousel object carousel
-
8/4/2019 McCann1
5/10
5
DVB Data Piping
DVB Data Piping uses MPEG TransportStream (TS) packets without any intermediatelayer
provides non-synchronised end-to-enddelivery of data through DVB networks
188 byte packets with 184 byte payload
DVB descriptor to identify data pipe
Any other mechanism relies on theapplication
1 0 1 1 0 0 1 0 1 10 1 0 0 1 1 0 0 1 0
0 1 0 0 1 1 0 0 1 0
-
8/4/2019 McCann1
6/10
6
DVB Data Streaming
Based on the MPEG Packetised Elementary Stream
(PES) construct that is used for video and audio:
Asynchronous data streams carry no timing
information (e.g. RS232)
Synchronous data streams allow clock and data
to be regenerated (e.g. E1, T1)
Synchronised data streams allow playback insync. with video and audio
Data
Audio
Video
-
8/4/2019 McCann1
7/10
7
Multiprotocol Encapsulation
Based on the MPEG section construct that isused for MPEG PSI and DVB SI:
optimised for Internet Protocol (IP) but
can be used for any other networkprotocol
datagrams can be fragmented into
multiple sections if they exceed
maximum payload of a single section(4080 bytes)
TCP/ IP
-
8/4/2019 McCann1
8/10
8
Data Carousel
Based on the MPEG Digital Storage MediaCommand and Control (DSMCC) data carousel
supports cyclic transmission of data
modules to receivers analogous to traditional Teletext
data is structured into Modules, Groupsand SuperGroups
could be used for software download to
receivers
.dll.dll
.doc
.pic
.xls
-
8/4/2019 McCann1
9/10
9
Object Carousel
Based on the MPEG DSMCC object carousel
supports cyclic transmission of structuredgroups of objects from broadcast server to
client (receiver) can download application, data files, data
streams and trigger events
typically used to provide interactiveservices
-
8/4/2019 McCann1
10/10
10
Conclusions
DVB data broadcasting specificationprovides a comprehensive set ofnetwork-independent protocols
capacity for data broadcasting can betraded against capacity for video andaudio in a totally flexible manner