Andrew de Quincey wrote:
On Monday 22 May 2006 20:34, Manu Abraham wrote:
Hello Andrew,
Andrew de Quincey wrote:
On Monday 22 May 2006 14:21, Johannes Stezenbach wrote:
On Mon, May 22, 2006, Klaus Schmidinger wrote:
Johannes Stezenbach wrote:
...
I also say it again: I am deeply dissatisfied that none
of the people you mentioned at the bottom of
http://linuxtv.org/pipermail/linux-dvb/2006-May/010076.html
seem to care enough to participate in the discussion.
(Not to mention that app developers also don't
seem to care -- after all these are the ones who'll have
to deal with the new API.)
Maybe we should just put the API change off for now. :-(
Well, as an application developer (VDR) I'd like to be able to
support DVB-S2, but I guess my knowledge about all this is too
limited to understand what this heated debate is all about.
I always thought that DVB-S2 is just "DVB-S with a new modulation",
IMHO the current use of DVB-S2 is just that, i.e. basically
the difference between the satellite_delivery_descriptor
as defined in EN 300 468 version 1.5.1 vs. 1.7.1.
(So it's actually not just a new modulation but also
the new roll-off factor.)
Current use of DVB-S2 to my knowledge is Premiere HD on Astra 19.2E.
If someone know other *current* uses of DVB-S2 please speak up.
Astra 28.2E has S2 streams. In the UK, nearly all of Sky's HDTV streams
are S2 - so its pretty obvious where they're heading with that.
I will check if the S2 descriptors are used in those NITs.
we have 2 modes.
(1) Normative Broadcast Mode (NBC-BS)
(2) Backward Compatible Mode
Only in Normative Broadcast Mode, we do have a S2 satellite delivery
system descriptor.
In the backwards compatible mode it is just DVB-S alone. There is only 1
stream in this case
Would such a stream be decodable by a DVB-S demod? If so, the Sky streams
_cannot_ be decoded by a DVB-S demod - already tried it :)
[snip]
Probably not Backward Compatible then.
The specs say like this ..
Backwards-compatible modes
The large number of DVB-S receivers already installed makes it very
difficult for many established broadcasters to think of an abrupt change
of technology in favour of DVB-S2 – especially where there is a receiver
subsidy and for free-to-air public services. In such scenarios,
backwards-compatibility may be required in the migration period,
allowing legacy DVB-S receivers to continue operating, while providing
additional capacity and services to new, advanced receivers. At the end
of the migration process, when the complete receiver population has
migrated to DVB-S2, the transmitted signal could be modified to the
non-backward compatible mode, thus exploiting the full potential of
DVB-S2. Optional backwards-compatible (BC) modes have therefore been
defined in DVB-S2, intended to send two Transport Streams on a single
satellite channel. The first (High Priority, HP) stream is compatible
with DVB-S receivers (according to EN 300 421 [3]) as well as with
DVB-S2 receivers, while the second (Low Priority, LP) stream is
compatible with DVB-S2 receivers only.
Manu
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