[mythtv] [S2API] modulation system and roll-off questions

wagabunda wrotkarz at gmail.com
Thu Oct 30 08:47:20 UTC 2008

(Sorry for my poor English)

I am finishing writing patch which provides support for DVB-S2
by the new S2API. It works transponder edition, a full scan
and scan the transponder with 8PSK transponders.

I have added a fields "Roll-off" and "Modulation system" to the screen
"transport edit". I also modified SatelliteDeliverySystemDescriptor,
DTVMultiplex and DVBChannel, of course.

I have a few questions:

- For which release to public this patch, release-0-21-fixes or trunk ?
I have yet to clear, so I modify it a little bit also.

- Roll-off require new fields in table dtv_multiplex. If roll-off is
always equal 0.35 in in commercial broadcasting, may set it on a
constant value ? I read that 0.20 and 0.25 are used only to the
professional broadcast.

- Modulation system require new fields in table dtv_multiplex, too.
If QPSK == DVB-S and 8PSK == DVB-S2 and QPSK with DVB-S2 is impossible,
this field is not required and code is simpled. Is it combination with
QPSK and DVB-S2 delivery is possible?


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