eng TELE-audiovision 1305

6-9. vLc Installation
124 TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine — 05-06/2013 — www.TELE-audiovision.com
6
7
8
9
involved and which means
they can be used in the network
with full bandwidth.
But Unicast has one problem:
what happens when
two, thee or even more users
request the same TV
channel? The server has
to then route the channel
individually to the various
TVs which will in turn put a
load on the network’s bandwidth.
It could happen that
the network connection between
the server and the
switch could easily be overloaded
by the vast amount
of data such that the video
output at the TV might become
intermittent or stop
altogether.
In cases like this Multicast
would be much more
elegant. With Multicast the
data packets are sent in
parallel to all of the connected
TVs and if you want
to, you can receive the data
stream, and if you don’t
want to, you simply don’t
access the data stream. The
server only needs to send
the data packet through the
switch one time. The switch
in turn routes the data packet
to not just one TV, but all
of the connected network
adapters.
But even this technique
has its drawbacks; just like
that all of the network connections
have to deal with
a heavy amount of data
traffic. When two non-participating
computers want
to exchange data between
themselves, a portion of
the network bandwidth is
no longer available. Even
though these two computers
are not being used to
watch TV, the line will still
be occupied with IPTV data.
Additionally, with Multicast
it’s typical for routers
that are not specifically
configured to not pass on
these data packets. If you
allow the router to configure
itself at home, Multicast
streaming over the public
Internet usually doesn’t
work because the routers
from nearly every Internet
provider can’t pass on these
packets. That’s why streaming
via the Internet for private
users only works with
Unicast. But wait! That fact
that it does work is proven
by all of the IPTV providers
that can be found in the Internet:
they are definitely
using Multicast to route TV
channels to an IPTV receiver;
they have special access
to the Internet.
Putting it all together, we
can say this: for private
IPTV applications Unicast
is in most cases the correct
solution; if you want to
serve multiple users with
IPTV, such as in hotels or
apartment blocks, then Multicast
is the way to go.
If you want to take part
in IPTV at home, you really
don’t need all that much: a
Linux receiver or a PC with
an integrated reception card
would be the server and a
normal computer or laptop
would be the TV device. In
most cases, Linux receivers
already have a web frontend
installed in the firmware.
If you call up the IP address
of the Linux receiver
in the computer’s browser,
you can choose a channel
and watch it on the PC.
To do this you click on the
small TV symbol to load an
m3u stream file. This is then
opened for example with
VLC and just like that you
can watch a live stream on
your PC.
This functions quite well
although with a Linux receiver
it is always one user
that can watch a specific
channel. Through Unicast
streaming, only one user