[mythtv-users] PVR-500 Dual Tuner

Bruce Markey bjm at lvcm.com
Fri Dec 3 02:07:40 UTC 2004

Brad Templeton wrote:
> On Thu, Dec 02, 2004 at 01:15:52PM -0800, Bruce Markey wrote:
>>Brad Templeton wrote:
>>>Of course, I have lived happily on a 1 tuner Tivo before trying to build
>>>my mythbox which will have two tuners, a pcHDTV and a wintv-150.  I
>>>sort of feel that a scheduling conflict is god's way of telling me I
>>>watch too much TV.
>>God probably didn't tell networks to pit shows that appeal to
>>the same demographic against each other in order to undermine
>>the Nielsen ratings of their competitors =).
>>on at 8:00pm Tuesday we most want to watch. However, there may
>>be four things on at 8pm Tue that I'd prefer over almost anything
>>else on at any other time of the week. So the advantage of
> This can be true in theory, and sometimes in practice, but how true
> is it really?

That's a good question and one that surprised me once I had
several tuners. 

>    Sometimes I feel the right answer is to just accept
> it, and that week watch only one thing.  You should never watch an
> inferior thing to fill your time just because you couldn't record
> a superior thing.

Agreed. Following that line of reasoning, it turns out that
most of the time there isn't anything on that I really need
to see and often superior things are on at the same time.
The question changes from 'what will fit in the schedule' to
'what are the things I'd most like to see'. If that means that
several things are recorded on Tuesday and nothing on Friday,
so be it.

>   Chances are, it will come on again (if it's not
> a sporting event.)   A clever PVR might even notice when it failed
> to record something due to conflicts, and remember to grab it for
> you in summer reruns (while not recording all the other reruns.)  Ie.
> add it to a permanent wishlist of sorts.

Myth shines here because unlike the system you are familiar with
where previously recorded shows are only remembered for 5 or 6
weeks and a first run feature is used to block reruns, myth keeps
it's previously recorded entries. It will remember which ones
you've seen before and only record the ones that were missed.
It's also a little smarted about letting you block out a showing
but still allowing that same episode to be recorded at another

> But I'm not like many.  When I got my Tivo I did watch more TV,
> even accounting for the fact that I could watch TV in 30% less time
> due to commercial skip.  It took effort to bring it back down.  Tivo
> suggestions are an interesting feature but can contribute to more
> watching.  On the other hand you can be bothered by the lack of variety
> without them and start surfing, which is of course bad (and very slow
> with digital TV.)

Variety is a good question or at least seems like a good question
when watching recordings rather than channel surfing. I thought
the suggestions were an interesting feature at first as well as
the promotional lists. However, The first week I said I liked
Letterman and it suggested another talk show, Oprah. I said no to
Oprah and a week later it recommended Letterman and not Oprah.
Three months later Letterman yes, Oprah no. I'm fairly confident
of it's talk show recommendations for next year.

But I found that I kept looking at these lists and came to realize
that what I was looking for was not the regular series that I'd
already formed an opinion about but the new titles I hadn't heard
of before(!). This lead to the What's New list now in Schedule
Recordings->Search Lists->New Titles. This is a slightly different
approach where there is a table of all the titles that have been
in the listings in the past (up to 11 months) then the New Titles
show all the future titles in the current listings that are not
in that list. So this is all the stuff that hasn't been on before.
Further, by using the view keys, Home and End by default, you
can see the list broken down by Movies, Series and Specials.
I've found many more interesting, unexpected things by looking
at these lists than I ever found in the suggestions. I also
believe I find more interesting things here than by channel
surfing because you only find things that happen to be on during
the times that you surf and even then you start watching from
somewhere in the middle.

> But for example, I deliberately don't get HBO, even though it has shows
> I would like to see, because I know I would watch more of it than I
> should.  (This decision was reinforced when comcast switched to requiring
> digital cable to get pay channels.  PVRs work much better with broadband
> RF style cable than with set top boxes, as we all know.)

I agree that they do but I'm not sure everyone knows that ;-).

> So I agree, sometimes multiple tuners will give you better quality
> TV.  But they will also make you -- at least if you are weak like me --
> from thinking about the decisions over what you really want to watch.

Glad you said that because it shows that I failed to express the
key point. Shortly before I had a DVR I was in the habit of watching
Dragnet at 6:30 before dinner. As I scheduled things on the DVR I
of course added Dragnet and started piling up episodes as I watched
other things. I finally had to come to grips with the fact that I
didn't need to record or watch Dragnet. The only reason that I was
watching it was because that was what was on at 6:30. I could
watch other stuff before dinner.

Now with multiple tuners you can take time and choice further. I've
watched Nova for decades and is probably my all time favorite show.
I now like reality shows like Survivor, Apprentice, Rebel Billionaire,
Biggest Loser, even this new The Real Gilligan's Island. I'd like
to watch all six of these shows (and not Dragnet BTW ;-) each week.
Other than Survivor and Apprentice on Thursday, the other four are
all at 8:00 on Tuesday. There's nothing I want to see on Friday so
why shouldn't I be able to watch another of these Tuesday shows on
Friday? So as far as thinking about the decisions over what you
really want to watch, that decision becomes more about what you
really want to see and less about what compromises you need to
make in order for things to fit.

> One thing multiple tuners can do though is facilitate automatic padding.
> All PVRs should automatically pad a few minutes extra before and after
> each program.   The before-padding would be invisible -- the cursor would
> start at the programmed start time, and a few minutes of rewind would be
> available.  The post-padding of course is not watched because you manually
> stop at the end. 

Myth had two different concepts for padding that are not intertwined
but are often confused. First, on the options page for any record
rule, minutes can be added or subtracted from the beginning and the
end. This information is used bu the scheduler in planning the schedule
and is always honored. If this creates more conflicts than tuners,
a show will not record if it cannot fit. 

There is also a global pre-roll and post-roll seconds. This is used
by the encoders at record time. The encoders can get a head start
ahead of the scheduled time of every show it is asked to record and
this is none of the the scheduler's business. If two shows are back
to back, the encoder goes from one to the next and quietly forgoes
the extra time.

> This is an obvious win, but harder to do on a single tuner.  The Tivo does
> it terribly.  Padding is manual and if you add it, the one minute overlap
> with another show counts as a conflict rather than a "no padding in
> this instance"
> Multiple tuners can give you full padding on all shows, which is a useful
> feature, but reduces your ability to use multiple tuners to avoid conflicts
> if you also have abutting shows.

What you can do with Myth is to set some preroll seconds so that
every show that isn't back to back will get this padding. If you
strongly suspect that a certain title is likely to need more time
and you don't want to risk missing, you can force the scheduled
minutes for that show.

> Many people seem to want multiple tuners so they can watch live TV while
> recording.  They haven't realized the error of their ways in wanting to
> watch live TV. :-)

Careful. We know that A/V test mode (live TV) is just training
wheels for people that haven't figured out what they have yet but
there are some people out there who get really worked up about how
they must channel surf and 'shouldn't have to record things'!?! ;-).

> Ideally, when given a variable length event (sports, news, academy awards etc.)
> a PVR would always do tons of padding in available free disk space.  As much
> as an hour.  Then it would mark this extra hour as "delete this if you need
> space, starting at the end."   Thus, if you watched reasonably soon after
> the event, you would not find it cut off.

Well if you are out of space there certainly must be better choices
to expire than the potential overtime finish of today's game. Murphy
says this would only happen when there is a thrilling triple overtime
buzzer-beater. It's like anything else with disk space; if you're
so tight that this one hour would make a difference then you don't
need to find an extra 2% of the disk space, you need twice as much

But, ya, with five tuners available I add 59 or 89 minutes to every
sports event with a priority of -2. The things just go off and
dominate a higher numbered tuner while my regularly scheduled shows
fit in there normal slots. For the past two years I've recorded
every College Basketball game (with overtime) the week before NCAA

> A really smart PVR would use shared knowledge from other viewers to figure
> out when the event actually ended (ie. almost everybody quit and deleted at 3
> hours 22 minutes) and then retroactively queue that space for re-use.
> (But it should never delete until actually needed.)   Or transcode the extra
> space really small.

I understand, but in the bigger picture the problem remains the
same. If a game is scheduled from 5:00 to 7:30 and there is a show
that you want to watch at 8:00 and the game goes past 8, you're

> Can you tell I have been frustrated to miss the end of a program?

More cards.

--  bjm

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