[mythtv-users] Tuning sub-channels on pcHDTV

[Daniel Thor Kristjansson]

]That's essentially correct... however, in this case it needs to be 16-1,
]16-2, etc.  There can also be some skew here... for example, in Boston,
]WGBX logical channel 44.4 is broadcasting on physical channel 43-5.  Go
]figure.  You can get the actual physical subchannel numbers from dtvscan
]that came with the pcHDTV card.

It's actually physicalfrequency-programnumber. Channels 16.1, 16.2 could
be 58-41, 58-32 in the freqid field, rarely will you see 12-1, or
anything XX-1 because program #1 is reserved for the NIT* in DVB
systems, so a ATSC+DVB compatible MPEG system would have problems with a
program id of 1. Also some of the transmission equipment used by
broadcasters in the USA is actually DVB equipment so they even transmit
a NIT. In this case you'll have real problems if you try to view
program #1.

*NIT provides the same TVGuide and channel info for DVB as the PSIP
tables do in ATSC.

If you specify a nonexistent program number, or none at all, MythTV
will try to find a program in the stream for you. It will report this
in the myth backend log so you can fix it (You might need to run
with --verbose record).

The reason it's not channel-subchannel or frequency-subchannel is
because MythTV does not cache any of the PSIP tables and they are sent
infrequently enough that using them to tune would take a long time.
Waiting for a PMT which reports the programnumber to pid mapping takes
less than a second so that is used instead. I'm working on parsing the
PSIPtables which is the first step to letting us cache this info in
MythTV's database.

I hope this clarifies things a little.

-- Daniel