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",
When i first heard about DVB-S2 , that is what i too thought. But as i
went ahead, somebody asked me to do a driver since somebody else was
busy. While i started it one of the vendors gave me fill go ahead flag
on it. I then went to read some specs and lo, it is not DVB-S +
8PSK/16APSK/32APSK
DVB-S2 has quite a lot of features. I think, this even caused the ATSC
guys to shelve off ATSC over satellite.
* It has variable slopes. (Nyquist Rolloff rates)
This eventually affects lot of stuff, since a larger falloff, helps in
wastage of transmitted RF power, thus saving energy, quite useful in
portable equipment.
* DVB-S suffers from climatic changes
DVB-S2 supports additionally quite a lot of things to make things better
* Physical layer Scrambling (helps to improve data integrity)
* Multiple streams
* Many more advanced features that it supports more than a MPEG2 TS
* some of the features allow it work in bad climatic conditions as well
* Saves bandwdth, not just because of H.264, but because of the sharper
filter slope, below a certain value the bandwidth is useless, it just
occupies bandwidth that which is not useful
so I would expect a new driver version that supports DVB-S2 to
just implement that new modulation and still call it "DVB-S".
This "...2" thing is IMHO just to make things clear to customers,
so they know that their old boxes can't handle it. From an application's
point of view it's still DVB-S, just with another modulation.
For people who just want to watch HD on the HP stream and _if_ you are
lucky, most probably you can use DVB-S + additional modulations
The reason being, you need to tell it to select the stream that which
you are interested in
I wouldn't even mind if the old and new driver weren't binary
compatible. I'd just write into the release notes of VDR that
as of version soandso VDR requires driver version XXX.
But then a again, what do I know...
Well, just making yourself small does not help in any way.
Manu
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