[mythtvnz] Use different tuner for adjacent recordings

[Stephen Worthington]

On Mon, 5 Apr 2010 21:15:37 +1200, you wrote:

>On Mon, Apr 5, 2010 at 9:06 PM, Aaron Whitehouse <lists at whitehouse.org.nz>wrote:
>
>> Sorry for a weekend of posts from me, but I'm sure that someone will
>> have a quick answer for this.
>>
>> I have managed to set up 4 virtual tuners on each of my dual physical
>> tuners. I want it so that, when there are two adjacent recordings, it
>> will use two different tuners, so that it will keep the 5 mins before
>> and 10 mins after with the recording.
>>
>> I'm pretty sure that there is a setting somewhere for this, but I just
>> can't see it anywhere. I find MythTV's setup screens really difficult to
>> navigate.
>>
>
>There is no global option for what you want (which is refered to as "hard
>padding") - you just need to set the padding in the recording schedules.
>
>There is an option in the settings for "Time to record before/after a show"
>in Setup->TV Settings->General->General (Advanced) (the 4th screen). This is
>for "soft padding" which means that Myth will only record the padding when
>there are no adjacent shows and adjacent shows are not pushed to other
>tuners. Sounds like you might have tried this before and I don't think it's
>what you want.
>
>Cheers,
>Steve

When you set up a recording rule, under "Schedule Options" you will
find the settings for "Start recording x minutes early" and "End
recording x minutes late".  These options have default values that you
can set up somewhere - but I can never remember exactly where when I
want to find them.  These options are hard padding - the scheduler
will obey them no matter what.  If you also have soft padding
specified, it will be added to the hard padding times except when
there is a back-to-back or otherwise conflicting recording.

Warning: If you use hard padding, during the overlap times, you will
be recording that channel twice at the same time.  This means you need
to ensure that you do not outstrip your hard disk's capability to
write that many files at the same time.  Eg, if you are recording 4
channels at the same time, and they all have back to back programs
with hard padding, then you will be writing 8 programs to disk at once
suddenly during the overlap.  That would probably be a bit much for
even a nice fast modern SATA drive.  I do have 4 recordings going at
once probably twice a week or so, but I have never had 4 all with
back-to-back recordings, so I can not say for sure that a single disk
would not cope.

BTW 5 minutes before and 10 minutes after is overkill.  I use 0
minutes of hard padding before and 3 minutes after, with 60 seconds of
soft padding before and 60 seconds after.  That works except for:

1) TV2 may need up to 2 minutes hard padding before sometimes,
especially early in the evening.
2) Late in the evening, you may need up to 10 minutes of hard padding
after.  This is almost always true for TV3 who always have the sport
greatly overrun their late news scheduled end time.  They really need
to schedule the late news as being 5 minutes longer than they do now.
3) Sky (if you are recording that) almost never needs any hard padding
as they are usually on time.  Which is good because setting any hard
padding makes it impossible to record programs whose times are back to
back (due to there being only one Sky tuner).

My setup is complicated by Sky needing rather different settings from
the DVB-T broadcasters.  Without Sky, I would just use no soft padding
and defaults of hard padding of 1 minute before and 4 minutes after,
with manual adjustments for the exceptions.

You may be tempted just to go with your suggested 5 minutes before and
10 minutes after.  However, that adds 25% to the storage required for
an hour program (and 50% for a half hour one) - and that will really
bite you eventually.  A TV3 HD 1 hour program takes over 5 Gibytes, so
even terabyte drives fill rapidly.