[opendtv] Re: Ofcom paves the way for UK HD on DTT
- From: Olivier Houot <olho_avatar_i@xxxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Sat, 05 Apr 2008 01:34:00 +0200
Bert,
you don't even have to go MIMO...
DVB-T2 is supposed to offer a 30% improvement over standard DVB-T, as a
minimum, while preserving comaptibility with current user antennas
(which implies single polarization broadcasts).
The french TNT will squeeze 3 HD streams in a standard 8Mhz channel (at
24 Mbps), using standard DVB-T.
It means on average each stream uses 33 % of the total.
So a 30% increase in bitrate would naturally allow for a fourth HD
stream in the same bandwidth, at exactly the same compression ratio.
The quality may even be slightly better, since statmux will operate in
more favourable conditions with more streams.
At the end of this page, it is mentionned that Harmonic can statmux 4 HD
streams in 25 Mbps (though one would like to have more details about the
resulting perceived quality):
http://www.broadcastingcable.com/article/CA6370674.html
Albert Manfredi wrote :
I am guessing that this freed up multiplex will be switched
over to DVB-T2, i.e. 32K mode, 64-QAM, 2/3 FEC, 1/8 GI (IIRC).
The most interesting aspect of this is that they are talking
four HD streams in the 8 MHz multiplex. That would indeed be
impressive.
I take it back. Not all that impressive.
I forgot the MIMO part of DVB-T2, so the 22 Mb/s becomes 44 Mb/s. So
sure, four HD streams should be readily doable.
http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP157.pdf
Bert
guessing that this freed up multiplex will be switched
over to DVB-T2, i.e. 32K mode, 64-QAM, 2/3 FEC, 1/8 GI (IIRC).
The most interesting aspect of this is that they are talking
four HD streams in the 8 MHz multiplex. That would indeed be
impressive.
I take it back. Not all that impressive.
I forgot the MIMO part of DVB-T2, so the 22 Mb/s becomes 44 Mb/s. So
sure, four HD streams should be readily doable.
http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP157.pdf
Bert
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