[linux-dvb] Re: DVB-T questions

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Måns Rullgård" <mru@mru.ath.cx>
> Is there any difference in the transport stream compared to DVB-S
> I should be aware of?

The NIT will contain a terrestrial_delivery_system_descriptor() instead of
a satellite_delivery_system_descriptor(), and there may be an additional
frequency_list_descriptor() for MFNs, that should be all the difference.

> Does DVB-T also use multiple programs per stream?

That's up to the broadcaster and the available bandwidth. HDTV in MPEG-2
probably eats so much bandwidth that a single multiplex can hardly carry
more than one service (the DVB term is "service", not "program", that's the
MPEG term).

> Are there regional differences in the DVB-T signals?

There are. Some countries use only UHF 8MHz channels (UK), others use VHF
7MHz channels (Germany), still others use 7MHz channels across the entire
frequency band (Australia), and still others might use 6MHz or even 5MHz
channels. Some countries use MFNs (Multiple Frequency Networks), others use
SFNs (Single Frequency Networks).

> I.e. will the same cards work everywhere?

No, as not every card implements the entire DVB-T standard, especially
since that has just recently been extended to cover DVB-H as well. E.g.
some initial cards were designed solely for the UK market and could only
receive 8MHz UHF channels - those cards were unsuitable for Germany or
Australia. Newer cards typically support 7MHz and 8MHz, but 6MHz support is
still an unknown.

And I haven't even seen any hardware components which support the extended
DVB-T standard with 5MHz channels, 4K FFT mode and Interleaving...

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany