[mythtv-users] Input priority

[Rod Smith]

On Wednesday 20 January 2010 06:18:04 pm Kevin Ross wrote:
> Michael T. Dean wrote:
> > [Lots of useful information]
>
> Okay thanks for clearing that up.  I guess the best way to give one input
> preference over another is just make sure it has a lower ID (i.e. is added
> first in mythtv-setup).

For INPUTS, yes. For CHANNELS, not necessarily. For instance, my cable company 
provides digital SD and HD versions of many channels (Science Channel, 
National Geographic Channel, etc.), so they come over the same input 
(Firewire in my case). My cable company gives the SD channels lower numbers 
than the HD channels, so the SD channels get favored by the scheduler. I 
suppose it would be possible to renumber these channels in MythTV, but then 
they wouldn't match the numbers used by the cable company, which could be 
confusing.

I've begun dropping the priority of SD channels with exact HD counterparts 
when I run into problems with SD being favored over HD. This restores HD 
recordings in most cases; since the SD and HD channels carry identical 
content, no recording is lost because of this change, although in my case 
there can still be conflicts (I've got just one cable box, so it's 
occasionally a scheduling bottleneck). If the SD and HD channels were to 
deviate in content, then lost recordings would become a possibility; but 
since the HD channel's priority is unchanged, the two have identical content, 
and only one can be recorded at a time, the only way I can think of to lose a 
recording this way is via a record-by-channel rule on the SD channel.

Going further, when the SD and HD channels are on different tuners but they 
have identical content, a conflict will result in the SD channel being 
recorded unless there are other shows scheduled at the same time on the SD 
input. (For me, this is very unlikely; I've got three analog SD tuners, which 
seldom get used any more.) If a later showing is available and there's no 
conflict at that time, though, it will be rescheduled for HD recording if the 
SD channel's priority is reduced. If I simply reordered the tuner cards in 
the setup and left all channel priorities at 0, this situation would cause 
the analog station to be recorded in SD at the earlier time. Which behavior 
is preferable is of course a personal matter, and might also depend on the 
shows being recorded.

Finally, I'm not too worried about conflicts causing problems I never see, 
since the MythTV scheduler flags conflicts in red. (The color varies with the 
theme in use.) Conflicts are therefore easy to see when I review upcoming 
recordings, so spotting them is easier than spotting suboptimal recording 
quality because the tuner's recording SD when an HD channel is available.

-- 
Rod Smith