[mythtv-users] Selecting from multiple cards (2xSAA7134, 1xNova-T) - using profiles?

[Bruce Markey]

Christian Hack wrote:
> I have a master mythbackend with 3 cards in it. Currently the first two
> (cardid 1 and 2) are normal analogue SAA7134 based cards. Cardid 3 is a
> Haupauge DVB Nova-T card. Essentially all cards can capture the same
> channels - just the DVB captures them digitally of course.

In other words, are you are using the same video source for
all three card inputs?

> Currently the DVB card is really only for testing since the although the
> driver is quite good, and the MythTV support is pretty good, it's not quite
> there yet. At the moment in particular it seems to be playing the 48kHz
> audio at 44.1kHz - still investigating.
> 
> I have been experimenting with the profiles stuff that's been recently added
> by Geoff Hausheer (sp?). From Isaac's description at the current top story
> on www.mythtv.org it was to support multiple types of cards. Is it meant to
> allow me to select to record on a particular card? i.e. Can I say record a
> particular show on the DVB card?

Actually, no. what determines which card will be used is the
scheduler. The first recording is assigned to the first card
etc. The card order is determined by the order you entered the
card inputs with setup. See the tricks and tips in:
http://www.mythtv.org/docs/mythtv-HOWTO-21.html#ss21.12

By default, the scheduler decides which overlapping show is
preferred by checking the type, length and channel. However,
now with rankings, the higher ranked show is preferred. The
highest ranked show will go to the first card input but the
second, third, fourth, etc. may still be assigned out of order.

So, if your DVB card was first, you could be sure that the
highest ranked show would be recorded on that card.

> Looking at tv_rec.cpp ->
> TVRec::HandleStateChange(void) it doesn't appear that it works like that. It
> appears that the profile is looked up _after_ the card had been selected.

It needs to use the codec params for the card that will do
the recording regardless what happened leading up to the
recording being assigned to that card ;-).

> So I'm trying to record unimportant shows to me, to test the DVB stuff. Is
> there anyway I can do this? Currently it only ever gets used if I'm already
> recording 2 things at once.

Exactly, pick three random things and one will be recorded on
the DVB card. Or use two different video sources but that
anticipates the next question...

> Also can anyone think of any tricks to record on both a DVB and one of my
> SAA7134 cards at the same time? I can imagine some simple database tricks
> could fool MythTV as long as I can select which card to record on.

I assume you meant to record the same show to compare the two
files. You can run "setup" again and create a record video
sources. Use a different name but configure it to grab the same
listings. Next, go into input connections and change the DVB
card to use the second video source.

Channel 3 for the analogue cards will be chanid 1003. Channel 3
for the DVB card will be chanid 2003 and can only be recorded
by the DVB card. Now if you choose to record the show a 8:00 on
1003 and 2003 you will get two distinct recordings of what we
know is the same show.

The down side of this is that when you go to the EPG you will
see two lines for every channel and you can't tell which row
goes with witch card. You could change the fields in the channel
table so that you can see which is which (channum?, callsign?
name?).

Of course, using this approach will make testing the DVB card
much easier because you can just choose a show on the DVB channel
rather than choosing three and not knowing which will be assigned
to the DVB card. 

Once you are happy that the DVB recordings are better than the
analogue recordings, empty the card info and rerun setup to
create one video source and add the DVB card first. The DVB
will always be used first and only lower ranked overlapping
shows will go to the analogue card(s).

--  bjm



--  bjm