[mythtv] pcHDTV: dual input

Chris Eldredge chriseldredge at comcast.net
Mon Dec 29 14:35:15 EST 2003

I know that some people are interested in trying to use the pcHDTV card
for both standard NTSC capture on /dev/video0 as well as ATSC HD capture
on /dev/dtv0.  The card supports this, but the question of resource
allocation comes to mind, since the card can only do one at a time.

I have not seen any updates indicating that this issue has been resolved,
so I will offer an idea that just occurred to me and then look into
implementing it, assuming no one has done something similar.

The pcHDTV has 2 coaxial inputs (main and aux).  My goal is to capture
ATSC transport streams from a UHF antenna attached to the main coax, and
capture analog NTSC streams from my cable provider, connected to the aux
coax.  Essentially, the problem is if mythtv is using one, it needs to
know that the other is not available.  Simply defining 2 capture cards
fails to address this concern.  Additionally, this method fails to
distinguish the main coaxial input and the auxiliary one (which means
mythtv would try to record NTSC from the antenna on main).

So now for my proposed solution:  the bttv driver declares "Television" as
the input source for the main coaxial input, but nothing for the auxiliary
input.  If the driver made available "Main Coaxial" and "Aux Coaxial"
inputs instead, MythTV can be configured using its existing features to
correctly perform resource allocation / conflict resolution.

Is that clear?  Does it make sense?  Is it possible?  Is there a better way?
Thoughts?  I'm going to continue looking into the feasibility of doing this.

The disadvantage is you wouldn't be able to tune NTSC signals from UHF/VHF
antenna.  But does anybody do that?


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