[mythtv-users] Multiple tuners with different channels

Joseph A. Caputo jcaputo1 at comcast.net
Fri Jul 18 11:49:13 EDT 2003


> -----Original Message-----
> From: mythtv-users-bounces at snowman.net
> [mailto:mythtv-users-bounces at snowman.net]On Behalf Of Dave
> Sent: Thursday, July 17, 2003 8:01 PM
> To: Discussion about mythtv
> Subject: RE: [mythtv-users] Multiple tuners with different channels
>
>
> Yes, that's it, it would be a kind of bit-mask.  It'd be a way of
> expressing this kind of info, without having to have a column per
> source or something, which would be unworkable.  I do apprechiate that
> doing operations on this kind of bit-mask number could be quite
> difficult compared to the simple = operaton.

Actually, that's the easy part...

[snip]

> Well, for a GUI setup, it need not be too complicated.  You could just
> have it as a grid, with a list of channels down the side, and sources
> along the top, and the user could just tick boxes to show which
> channels each source had.  Also, I don't see why mythfilldatabase
> should be different, since it'll just grab listings for ALL channels
> regardless of which sources they're available to.

It's not the GUI that'd be complicated, it's the underlying method by which
video sources & channels are set up.  When you specify a video source, it
uses an external program (tv_grab_<region>) to grab your selected provider's
list of channels.  Yes, a 'channel' (here meaning a television network) may
exist in more than one source, but it will not have the same frequency in
both sources.  So, we *do* need to maintain separate database entities for
each channel, even if they are the same television 'network'.  What we would
really need would be a way for Myth to be able to determine that two
channels are equivalent in terms of content (a 'networkid', i.e., 'CNN'
(network name), 'WPVI' (television station callsign) or a numerical
equivalent).  If you have only one video source, you get a 1-1 mapping of
networkid <-> chanid.  When you add subsequent sources, you would get
presented a list of the new channels with an opportunity to map them to an
existing networkid.  Any new channel not mapped to an existing network
automatically creates a new network for itself.

Next, (and this is, I think, the really tricky part) the trick is modifying
the scheduler and TV tuning code to consider the new concept of a networkid
and how it relates to channels and video sources.  Also, how does all of
this affect the concept of channum/chanid and how is it all represented in
the EPG?

I'm not saying it's impossible, but when you look at all the discussion and
effort that went into something as conceptually simple as separating the
concept of channum/chanid from the tuner frequency, and consider that this
is (IMHO) a much more complicated idea, you begin to see that it's not as
simple as all that...


> And you shouldn't need to specify a "favourite" card for each channel.
> It could still treat the first card as favourite overall, but if a
> channel isn't available on that card, it'll just drop to the next card
> and so on.

Actually, the concept of a favorite card per channel is (IMO) much simpler
to implement and is applicable even if you have only one video source (but
multiple tuners).  It's quite possible that different channels might have
better picture quality based on a particular cabling & tuner card setup.

Anyway, I don't mean to discourage you; I'm sure that if there is enough
interest someone will tackle the concept you've put forth; I just wanted to
give you an idea of the magnitude of what you're suggesting.  Of course, I
could also be completely wrong in my assessment of the complexities involved
:-)

-JAC



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