[mythtv-users] Master backend with no capture card

Michael T. Dean mtdean at thirdcontact.com
Tue Feb 2 01:24:41 UTC 2010

On 02/01/2010 07:41 PM, Dale Pontius wrote:
> I found this issue discussed on the list back in 2005, but no definitive
> answer given.
> I'm looking to build a new server soon, and with terabyte drives so
> cheap, I'm looking at moving my Myth storage down to the server.  Since
> the server is also guaranteed to be running 24x7, I'd also like to move
> the Myth master backend to that machine.  But it doesn't work to get an
> antenna feed down into my server closet.  I works much better to make my
> current (only) backend machine into a slave backend, and set up WOL so
> the master can kick it when it needs to record.
> I do have an old unused capture card that I could stick in and
> configure, but I really can't get a signal there.
> Is it possible to run a card-less master backend?  Lacking that, can I
> stick a card in, set it up properly and associate it with my Schedules
> Direct lineup, then somehow configure it so it'll never get used?
> (Since it won't really work, anyway.)

A master backend with no configured (in MythTV) capture cards or
not-fully-configured (in MythTV) capture cards is the same as a backend
with no capture cards (technically, not-fully-configured is worse as it
will eventually cause problems with other cards/video sources/inputs). 
So, that means if you add a card just to have a card, you need to create
a capture card in MythTV, then create a video source for that card, then
create a channel for that card, then associate that video source with
the appropriate input on that card.  At then end, you have a useless
card that's sucking power and costing you money (the hardware cost plus
the power cost).

Therefore, if the card (hardware) itself is going to be useless, an
easier solution is to cut out the middle man (the card) and just
configure a useless card without the hardware.  So, to make sure Myth
still operates properly in all situations, you can create a(n equally
useless) "test" capture card in the master backend (then create a video
source for it that specifies "No grabber" for the grabber, define one
fake channel, then associate that video source with the capture card). 
See http://www.gossamer-threads.com/lists/mythtv/dev/217058#217058 for

Eventually, we may support tuner less backends.  Until then, this is a
nice easy way of putting a harmless (and zero-cost) capture card into a
backend.  (OK, if you point it at a 10MiB MPEG file, then it is costing
however much 10MiB of HDD space goes for these days, but...)  And,
though the "test" capture card itself isn't supported, the backend's
configuration (as a backend with a valid capture card defined) is supported.


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