[mythtv-users] is mythtv smart enough to do this (overlap/back-to-back) with recordings?

[Daniel Walton]

Let's say you have one capture card just to keep the example simple.  You have
two shows you want to record that come on back to back on the same channel and
you want to record an extra minute at the beginning and end of each show:

Show 1 - 4:59-5:31 (originally 5:00-5:30)
Show 2 - 5:29-6:01 (originally 5:30-6:00)

At 5:29 why couldn't myth start writing the recorded content to the show 2 file
in addition to writing it to the show 1 file?  It only has to write to two files
at once for the next two minutes and that would resolve the conflict.  It seems
like that would be easier than trying to keep just one copy of the 5:29-5:31
content that you magically play as a part of Show 1 and Show 2.

Daniel

On Wed, 26 Jul 2006, Michael T. Dean wrote:

> On 07/26/06 12:10, Peter Watkins wrote:
>
> >On Wed, Jul 26, 2006 at 11:43:51AM -0400, Michael T. Dean wrote:
> >
> >
> >>On 07/26/06 10:31, George Nychis wrote:
> >>
> >>>I have 2 shows recording back to back...
> >>>
> >>>First show: 5:00pm-5:30pm
> >>>Second show: 5:30pm-6:00pm
> >>>
> >>>Both shows are on the *same* channel.
> >>>
> >>>If I set the first show to end 1 minute late, and I have only 1 tuner,
> >>>is mythtv smart enough to put the [overlapping] minute into both recordings?
> >>>
> >>Nope.
> >>
> ...
>
> >If Myth should expect the same data for both recordings (e.g., both are
> >HDTV, or both use the same recording profile), then I think Myth ought to be
> >smart enough to copy/splice the overlap video into both recordings and only use
> >one tuner. At least for schedules that are driven by program guide data (vs.
> >VCR-style hard-coded date/time schedules), this should work really well.
> >
>
> OK.  So let's say I'm recording a high-priority (+99) movie from
> 3:30-5:30.  From 5:00-5:30 and 5:30-6:00 are two episodes of a
> medium-priority (+50) show.  Since the TV show often goes a few seconds
> beyond the scheduled time, I set an end late of 1 minute on the TV
> show's recording rule.  So, assuming these are the only shows I'm
> recording during this time period and I have two capture cards, I would
> have recordings as shown:
>
> Card 0 - Movie - 3:30-5:30
> Card 1 - Show - 5:00-5:31
> Card 0 - Show - 5:30-6:01
>
> Notice that the two episodes of my show are being recorded on different
> capture cards.  So, you may ask, "Well, why isn't Myth smart enough to
> record both episodes of the show on the same card?"  Well, Myth /always/
> uses the preferred input for capturing--assuming if you record it, you
> want it to be high quality.  If multiple shows are being recorded at the
> same time, the highest priority show is recorded on the most-preferred
> input.  If all your inputs have the same specified priority, the
> lowest-numbered input wins the tie.  If we randomly shuffle around
> capture cards, we might get the high-priority movie recorded on a BTTV
> card and the episodes of a medium-priority show recorded on a
> high-definition card.  Myth shouldn't be making this decision--the user
> should do so by rearranging priorities (possibly with a recording
> override for the show).
>
> So, as Peter suggested, why not /if/ the cards are identical (i.e. both
> PVR-x50's) still record the overlap to both files even though it will be
> on different cards?  OK, imagine now a system with 2 PVR-x50's and a
> BTTV card.  Can you say, "Non-intuitive behavior that's hard for the
> user to predict."
>
> Now, keeping all this in mind, let's say we have 2 PVR-x50's and a
> distributed Myth system with 2 backends.  At this point, how would we
> get the data from a capture card on one backend to the filesystem on the
> other backend?  Even if both backends write to a common networked
> filesystem, we still have to ensure one of them handles writing the file.
>
> This is /not/ the "principal of least surprise."  Imagine all the
> questions we would see about why /sometimes/ (in the general sense
> because no one has been able to determine the pattern from empirical
> evidence) Myth records the overlap successfully, but sometimes it doesn't.
>
> Just because it /seems/ easy to do on a simple MythTV system, don't
> forget that Myth supports many more configurations.
>
> Also, if I put a start early of 1 minute on my TV show's recording rule,
> I have a conflict:
>
> Card 0 - Movie - 3:30-5:30
> Card 1 - Show - 4:59-5:31
> Conflict - Show - 5:29-6:01
>
> At this point, the /only/ things I can do are:
>     - adjust my recording rules (i.e. with a recording override)
>     - get more capture cards
>
> Which means, that for both situations (recording an overlap or
> preventing conflicts due to overlaps), the /right/ solution is to add
> more capture cards.
>
> Mike
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>