11-05-2011, 03:16 PM
Submitted by:
Hemant Sharma
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ABOUT TV !Television (TV): specifies the medium of communication that operates through the transmission of information to the users as pictures and sounds for their interpretation &entertainment.MODES OF TV TRANSMISSION
Historic view-TV transmission from towers,
distribution over a cable n/w or beamed directly
from Satellite (VSAT).
Modern view-TV, Telephone services & high
speed internet access will be delivered over
present broadband DSL Network on a single
connection.
Types Of Transmission
MULTICASTING- A multicast stream is sent to a multicast group internet address. When a user selects a live channel, a request to join the group of viewers associated with the relevant multicast address is sent from the set top box to the equipment in the local telephone exchange.
UNICASTING- A video-on-demand service is unique to each viewer & delivered as a unicast stream. It is sent to a single internet address in response to a request from the receiver.
Evolution [of the TV]
The Origin of IP-TV
CONVERGENCE
Definition of IP-TV
IPTV essentially has two components:
Part 1: Internet Protocol (IP): specifies the format of packets and the addressing scheme. The protocol establishes a virtual connection between a destination and a source. IP allows you to address a package of information and drop it in the system, but there’s no direct page link between you and the recipient.
Part 2: Television (TV): specifies the medium of communication that operates through the transmission of pictures and sounds. We all know TV, but here we are referring to the services that are offered for the TV, like linear and on-demand programming.
Technologies involved in IP-TV :
1. Broadband – The key element
As per TRAI:
“An always-on data connection that is able to support interactive services, and has the capability of minimum download speed of 256 kbps”
Note: This definition for throughput may undergo up
gradation in the future.
2. xDSL
xDSL Family Tree
Symmetric DSL
Provide identical data rates upstream & downstream
Asymmetric DSL
Provide relatively lower rates upstream but higher rates downstream
Four main variations of xDSL exist:
ADSL-Asymmetrical Digital Sub’s Line
HDSL-High bit/data rate Digital Sub’s Line
SDSL-- Symmetric Digital Sub’s Line
VDSL-Very-high-data-rate Digital Sub’s Line
Some DSL Standards
ADSL Modulation
ADSL2+ Potential
Basic Architecture of ADSL
Extension of ADSL to IP-TV
IP-TV NETWORK ARCHITECTURE
COMPRESSION TECHNOLOGY
H.264 is mainly used
It has 50% more compression efficiency as compared to MPEG-2
Picture quality is retained at low bit rates
It enables the broadcast of HD over IPTV
Comparison between H.264 & MPEG2
SECURITY ISSUES
DIGITAL RIGHTS MANAGEMENT(DRM)
WATERMARKING
Content Services in Triple Play
Broadcast type
IPTV
Pay TV
Hi-Fi Radio
Electronic Programme Guide (EPG)
Multicast Streaming
Live Streaming for VOD
Progressive Downloads(Video , gaming,music downloads)