A revolutionary
way to deliver live digital TV and Radio broadcasts is by using IP
Multicast over standard network cabling. The Wandsworth Group has
developed a cost-effective, easy manageable method of delivering
digital quality television (DVB) and radio (DAB) from a variety of
sources whether the transmission is free-to-air or encrypted.
The picture and sound quality are excellent
and is the same to all end-users regardless of cable runs and number
of users. The output from the system is pure digital MPEG, which
stands for Moving Picture Experts Group, the name of a family of
standards used for coding audio-visual information (e.g., movies,
video, music) in a digital compressed format.
Each IPTVServer is supplied with a specific selection of appropriate tuners.
By using IP Multicast each live transmission is identified as a unique
group IP address. The end-user is able to join and leave a group of their
choice as they see fit, exactly the same as normal TV channel changing.
The channel change time is comparable with normal TV and the quality of
the signal is not degraded by the number of users.
DVB-T transmissions are received from land base transmitters and the channels
are divided into 6 groups called Multiplexers; each DVB-T tuner is assigned
to a specific multiplex, they cannot tune to more than one multiplex. DVB-S
transmissions
are received from any satellite used for Digital
TV distribution; the channels are dividedinto many groups called
Transponders; each DVB-S tuner is assigned to a specific transponder,
they cannot tune to more than one transponder. DVB-C transmissions
are received over cable and the service carrier defines the groups.
In all three cases each tuner card can handle up to a maximum 8
channels ofTV and Radio.
The quality of the service is dependent on the specification of the Ethernet
switches used in the network; Wandsworth has already certified certain
switches from Extreme and Allied Telesyn and is happy to test other manufacturer's
brands. A detailed list of tested and approved switches is available on
request.
The transmissions can be received by any PC provided with Wandsworth’s
IPTV Client application or by a flat panel or conventional TV using Wandsworth's
Media Gateway and Local Distribution (LDU) devices as shown in the schematic.
