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TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine
— 07-08/2013
—
FEATURE
Self-made IPTV
1. To the right TS Reader Pro shows the complete content
of a transponder stream together with each of the PIDs. The
streaming parameters can be defined in the Settings menu.
2. PIDs that are to be filtered out of the transport stream can
be entered in the “PID Removal” field
3. In the upper field the individual channels can be streamed
via various IP/Ports
channel, put them back to-
gether and then display the
resulting data stream.
Two technical terms that
are quite often used in this
scenario are:
Multiplexer
:
The device responsible
for creating the transport
stream. Various incoming
data streams are converted
into small data packets and
inserted back to back into
the transport stream.
De-multiplexer
:
The device that extracts
the individual streams from
the transport stream and
Vitor Martins Augusto
With digital TV transmis-
sions each frequency rep-
resents one transponder.
Multiple TV channels can be
found on a single transpond-
er, the number of TV chan-
nels depends on the picture
quality of each individual
channel.
If quite a few channels are
to fit on a transponder, then
the picture resolution would
be reduced while at the
same time the compression
rate would increase. The re-
sult would be a TV channel
with a narrower bandwidth
and a corresponding reduc-
tion in picture quality.
Thanks to the new HDTV
formats that, for example,
are used by DVB-S2, DVB-
C2 or DVB-T2, higher band-
widths per channel are now
possible and in turn larger
compressions can be ob-
tained with these MPEG4
methods compared to
MPEG2 that is mostly used
by DVB-S, DVB-C and DVB-T.
In each case it involves a
continuous data stream that
basically consists of only
ones and zeros. How can
such a data stream transport
various audio and video car-
riers together with NIT, EPG,
Videotext such that all these
channels are available simul-
taneously at the same time?
It’s very simple: the data
of each channel is placed
in small packets and incor-
porated into the transport
stream one behind the other
in very short time intervals.
If you want to watch a
specific channel on the tran-
sponder, the receiver would
have to capture the match-
ing data packets for that
