[mythtv] DVB scan and satcodx lists

Taylor Jacob rtjacob at earthlink.net
Tue Nov 16 19:44:54 UTC 2004

> I just tried the DVB setup of mythtv with the latest patch and apart
> from waiting for the CAM which does not exist the channel scan seems
> to work. It is a little slow, though.

Glad to hear that.. Also nice coming from someone whos name is plastered all
over linux dvb related things as well..

> Since I decided to start working with mythtv now I would like to help
> with the DVB development. So my question is, if it has been considered
> to use transponder lists from satcodx to help with the DVB-S channel
> scans. The NIT scan may be fine for DVB-T or DVB-C where you only have
> a few channels compared to DVB-S, but with 4 satellites to scan that
> is a little slow and NITs are not aways complete.

I personally am not a fan of the SatCoDX lists.. In North America at least they
don't seem to always be right, and its also not very easy to just get a list of
Transponders.   On the other hand John and I had talked about using the
"Seeding" files that dvbscan uses to populate a transponder list.

I haven't seen the NITs be incomplete very often.  I am aware that some of the
satellites in Germany don't send a complete NIT for the satellite, but only for
the transponders that they operate on, which means that you need to tune to a
few different transponders to get a complete scan of the Satellite (I can see
this being a pain in the arse).

> So I would like to be able to feed mythtv lists from satcodx or libdvb
> or any other scanning program.

As above I was thinking libdvb might be nicer, but one advantage to satcodx that
libdvb won't offer is flaging transponders as feed transponders.  In the long
term I wanted to setup myth to search a list of transponders marked as "feed"
whenever it wasn't pre-occupied recording and store all of these shows in a
"Feed" group..  Which using SatCoDX might faciliate this much easier than

> If noone is working on that, I would be willing to start with that and
> appreciate any suggestions.

That would be good.  Another type of scan that John and I had discussed in the
past was for DVB-T/C checking every frequency combination that is possible for
a lock, so you could do a completely blind scan if you told myth what country
you were in.. This type of scan would also be how you would have to do ATSC
scanning.. This of course will become more of a big deal to me if the Dvico
Fusion3 Gold card ever gets support under linux-dvb since I am not a far of the
pchdtv drivers..  Of course this only applies to those of us in North America
and South Korea..

> I can also help with other problems you may have with DVB. I work or
> worked on several DVB card drivers and wrote the first application
> examples for the DVB API (like libdvb and dvb-mpegtools).

One major thing I would love to see added to the linuxdvb drivers is the ATSC
CRC checks.  I have done some testing with the ATSC feeds over DVB-S I can get
in North America and I just ignore the CRC for now, and it realy ought to be in
the linux-dvb drivers at some point.. I am not sure how you would tell the
drivers which CRC routine to use since the PAT and PMT in ATSC use the MPEGTS
CRC, but the other tables TVCT, etc use the ATSC CRC..   This kind of makes
things a pain.. Then again ATSC just makes me mad about how the US has to be
different.. No point in starting that argument here..

> I don't know much about mythtv yet, so I will have to learn about it's
> structure a litte more.

Well ask away.. I'll be glad to help you along..

More information about the mythtv-dev mailing list