On Thu, May 25, 2006, christophpfister@xxxxxxxxxxx wrote: > >On Thu, May 25, 2006, christophpfister@xxxxxxxxxxx wrote: > >> >On Tue, May 23, 2006, christophpfister@xxxxxxxxxxx wrote: your quoting is broken :-( > >- hierarchical modulation: one DVB-S and one DVB-S2 signal are > > combined via a hierarchical mapper; the DVB-S2 signal > > is _SIS_ (note that the hierarchical mapper is located *after* > > PL header insertion); a DVB-S receiver will only see the > > DVB-S stream; a DVB-S2 receiver will see the DVB-S2 stream, > > however to do so it needs to be set in a special BC mode > > (because of the "asymmetric 8PSK constellation"); > > again our API would use DVBFE_DELSYS_DVBS vs. DVBFE_DELSYS_DVBS2 > > to select HP vs. LP stream, but also needs the obc_mode flag. > > That's not quite correct. While a DVB-S device receives only the HP stream, > a DVB-S2 device receives *both* streams. > So the most used mode is MIS. The stream_id is used in this case to select > either the lp or the hp stream. I'm looking at EN 302 307 figure F.1. It shows that the HP stream is a DVB-S stream of I/Q-bits (outer & inner coding, not yet spectrum shaped and modulated) according to EN 300 421, thus it cannot have a stream_id. Please explain why you think hierarchical BC mode uses MIS and stream_ids to select HP/LP. It contradicts my understanding of the standard. The frame structure of DVB-S2 is totally different than DVB-S, so a DVB-S2 demodulator will not be able to demodulate a DVB-S stream. E.g. STB0899 contains two completely seperate demodulators for DVB-S and DVB-S2 mode. Thus I think one uses DVBFE_DELSYS_DVBS vs. DVBFE_DELSYS_DVBS2 to select the HP or LP stream. > >> >- NBC-BS == "normative broadcast mode"? > >> > >> Yes. > > > >After sleeping it over, I think NBC-BS and > >"normative broadcast mode" are not equivalent. > >DVB-S2 NBC-BS has mandatory and optional parts > >(EN 302 307 table 1), and "normative broadcast mode" > >means "the mandatory parts of NBC-BS only". > > > >I.e. MIS is optional and thus nor part of > >"normative broadcast mode". Thus what EN 300 468 > >means to say is: "If you only use the mandatory parts > >of NBC-BS you don't need the S2 descriptor". > > NBC-BS doesn't need the S2 descriptor (as explained earlier). > But still NBC-BS == "normative broadcast mode", e.g. because the backward > compatible mode isn't the same as normative broadcast mode. It really a bummer that EN 300 468 uses the term "normative broadcast mode" without defining it, but I am now convinced that "normative broadcast mode (NBC-BS)" means "those parts of NBC-BS which are mandatory", i.e. "normative broadcast mode" means a subset of NBC-BS. Look at EN 302 307 table 1. E.g. MIS is NBC-BS, but not part of "normative broadcast mode" since MIS is an *optional* feature of NBC-BS. Johannes _______________________________________________ linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
