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

Steve Hodge stevehodge at gmail.com
Sun Jul 30 06:06:57 UTC 2006


On 7/30/06, chris at cpr.homelinux.net <chris at cpr.homelinux.net> wrote:
> On Sun, Jul 30, 2006 at 02:47:07PM +1200, Steve Hodge wrote:

> Just because a
> proposal solves a particular problem doesn't automatically mean
> it's an improvement over the status quo if it closes off an avenue
> of development, though.  If you do that often enough then the
> system reaches a point where the only way forward is with a blank
> sheet of paper.

That's fine, but I don't see how adding the ability to record the
overlap between two adjacent programs on the same channel would
constrain other development.

> > Highest priority show gets scheduled first. It gets the highest
> > priorty tuner. Any other lower priority adjacent shows on that channel
> > also use that tuner.
>
> What about when the shows having sequential priorities are not in
> sequential time-slots?  Imagine that the top priority show is
> channel 38 from 1700-1900 and it gets tuner #1.  The next highest
> priority is channel 51 from 1930-2200.  Since there's no conflict
> it also gets tuner #1.  Then somewhere far down the list you have
> an ultra-low-priotity show on channel 38 from 1900-1930.  If you
> have padding then something's gotta give.  How much of a disparity
> in priority can you tolerate when bumping the #2 show from the
> high-quality tuner?

The obvious solution is for people who want that much control to
simply exercise it in the same way they currently do when they don't
like what the scheduler has planned: use overrides.

As a default I'd prefer to see the scheduler maximise the number of
shows that will be recorded, though some might prefer a user specified
threshhold.

> Do you really want to record a movie on a
> noisy SD cable feed so that an episode of "Family Guy" that just
> *happens* to be adjacent to another high-priority show on the HD
> tuner can take advantage of the shared padding?  Even if all three
> shows were on the same tuner, what do you do at 1930?

Yes, I'd rather have the default behaviour to be to record the movie
on an SD feed rather than miss something else I've asked for. If I
didn't like that outcome I'd still have the options of altering the
padding so the same tuner can handle both or overriding one of the
scheduled programs.

> "It won't scale" *is* a fundamental objection if the goal is to
> create an easily extendable and maintainable system.

But you still haven't explained how it won't scale. All you've done is
bought up a few cases that can be used to argue that maybe the
scheduler won't do what the user might want, because of the priorities
applied. Those sorts of issues are a matter of deciding how it should
work, they are not a good argument against the functionality because
the user would still be getting more chances to record that they
currently do. Scalability implies that the "problems" will get worse
if there are more tuners and I don't see that happening.

> Using fragments is only complicated because people are used to the
> concept of a recording as a monolithic block and therefore *think*
> that other solutions are too complicated.

Do you think that fragments are going to be less complex (or less
intrusive, if you like) to implement than the "recording into two
files at once" enhancement?

I think it's going to be difficult to coordinate the fragments. My own
system, for example, has an tuner recording the output of a satellite
box (for encrypted channels), and a DVB-S card that can receive a
subset of the same group of channels. But the same channels on the two
tuners are not perfectly synchronised. How do you propose to handle
that seemlessly?

Steve


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