[linux-dvb] Re: [OT] Reality

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

From: "Gavin Hamill" <gdh@acentral.co.uk>
> I'm not sure what DVB-SI is
> (is the one pertaining to CAMs and encryption?)

No, DVB-SI is "DVB Service Information". Look at it this way: MPEG-2
defines the _base_ of a digital television system, but leaves many things
open, e.g. how to transmit network-specific reception information, service
names, etc.

Thus, DVB-SI is what "completes" MPEG-2 to a full digital television
system, DVB. ATSC is a different "completion" of MPEG-2 and uses different
data formats for service information. I think the main difference is that
DVB-SI uses the same table and descriptor format that MPEG-2 uses, while
ATSC uses fixed-size tables, which are easier to parse, but are not
consistent with the MPEG-2 base.

> It's interesting to note that the reason we dropped from using QAM64 /
> FEC2_3 was to 'improve the picture quality' (reduce UNCs in fringe
> areas) but the lower available bitrate means each station is now
> transmitting a lower quality picture. Again, so much for progress...

Oh, so there's no more QAM64 DVB-T in the UK? Hmm, I think it will _have
to_ return some day, because HDTV is very bandwidth hungry :-)

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



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