[mythtv-users] is this possible (multiple tuners and sources)

Bruce Markey bjm at lvcm.com
Thu Aug 11 01:47:57 UTC 2005

Dylan Keon wrote:
> On 08/10/2005 12:01 PM, Bruce Markey wrote:
>> Dylan Keon wrote:
>>>   My goal is to have the two PVR-250s record analog cable (already 
>>> working), and the PVR-150 record OTA broadcast signals via my rooftop 
>>> antenna since the reception of local channels stinks on our analog 
>>> cable.
>>> I set up a new video source called "antenna" and configured a new 
>>> "local broadcast" channel listing for my area at zap2it.  However, 
>>> it's not clear to me how this will get handled in the EPG.  For 
>>> example, channel 7 on analog cable is Discovery, while channel 7 on 
>>> broadcast is PBS. 
>> The one marked "7 DSCP" and shows MythBusters is Discovery, the one
>> that says "7 PBS" and has Nova is PBS. Oddly, this is the second
>> time this has come up recently. If you schedule MythBusters, it won't
>> bust myth and record Nova by mistake =).
> Ok, good :-)
>>> After running mythfilldatabase these both appear in the EPG, but 
>>> where channels are the same (i.e., channel 9 is the same station on 
>>> both cable and OTA), there is only one entry in the EPG.
>> Correct. By design. If the channel number and callsign are the same,
>> it does not show both. I have NBC on 3 for analog and on 3 and 123
>> digital (chanids 1003, 2003 and 2123 respectively). The EPG shows
>> one line for NBC on 3 rather than two identical lines next to each
>> other but does have another line for 123. If another input had
>> station "KRAP" on 3 (3003), the EPG would include both channel
>> 3 stations.
> Nice callsign ;-)  I just took a peek via mythweb and I can see that my 
> EPG is also arranged as you described.
>>> I want local channels to be recorded on the PVR-150 by default, using 
>>> the local broadcast channel listing unless there is a conflict, in 
>>> which case they would get recorded on one of the PVR-250s.  
>>> Cable-only channels would always get recorded on the PVR-250s.  Is 
>>> all of this (or any of this) possible?
>> This has all been solved long ago. You actually have some choices...
>>> I could just delete the duplicate broadcast channels from the cable 
>>> lineup, but then that would eliminate the possibility of using the 
>>> cable as a backup to resolve conflicts.
>> Myth treats two channels with the same callsign as being the same
>> station and are interchangeable. Which channel is used for a show
>> on that station is deterministic. If all else is equal, by default
>> the scheduler will choose the lowest numbered input that has that
>> station available.
> Ahhh, this is good to know.
>> There is also an option on the mythtv-setup Input connections page
>> for "Input preference". If you set this one higher than the others,
>> that tells the scheduler that it is better to record from this input
>> whenever possible rather than to record from the other inputs.
> Great, I think this is what I need!
>> There is a subtle difference with "Input preference" vs just relying
>> on the lowest input number winning. Say you have your "antenna"
>> input first (probably not right now because you added it last)
>> and there is a high priority show at 7 and a lower priority show
>> at 7 and 10 on a channel that is available on both sources. If the
>> input preference is the same, the high priority show will record at
>> 7 on "antenna" and the lower will record at 7 on the channel from
>> the other source. If you raise the input preference for the antenna
>> input, it would record the high priority show at 7 and the lower
>> priority show at 10 when it can fit it on the preferred input. If
>> there was another conflict at 10 then it would again use the other
>> source at 7.
> When I installed the PVR-150 it appeared as /dev/video0 so I believe it 
> is the lowest input number.  I had to edit the PVR-250s in mythtv-setup 
> since they are now /dev/video1 and /dev/video2.

Oh, that's the device number. This has confused the heck out if
other people if the new card got /dev/video0 and the old device
was bumped up. However, I was referring to the myth DB config
mythconverg.cardinput.cardinputid. This is determined by the
order that you entered your card information through mythtv-setup.

> Great example.  Regarding the scenario where the same show is airing at 
> 7:00 and 10:00 on a channel available to both sources - how far into the 
> future would myth look to make sure a show gets recorded on the 
> preferred input?  How aggressively does myth do this?  For example, you 

For all the listings you currenly have. Usually a little less
than two weeks.

> wrote that the show wouldn't be recorded until 10:00 so that the 
> preferred input could be used.  Would myth look forward as far as a week 
> to find a slot when the show could be recorded on the preferred input? 

In practice this rarely happens. Either a network primetime show
is shown only one time or a cable show is repeated several times
(possibly a dozen or more times). It is very rare that a second
showing is any more than two or three days away.

> If that's the case I would rather just have it record on the other 
> source so I could have it available sooner.

Right, and you can always do this. If the scheduler chooses another
showing, the title on the "Upcoming Recordings" page will be white
and the status will be "L". You can press Enter and click "Record
anyway". The bigger question is if the quality is enough different
that you wouldn't mind waiting a few hours or a day on a few lower
priority shows when there is an overlap. I've always found that if
I'm recording two or three things at a time some evening, I'm not
going to watch all of it that night. If a lower priority show is
recorded on a better input tomorrow, that's perfect, I may not get
to it for several more days anyway.

However, if you find time is more important than quality then don't
use the input preference.

Here's my cardinputs:

mysql> select cardinputid,sourceid,cardid,preference from cardinput order by cardinputid;
| cardinputid | sourceid | cardid | preference |
|           1 |        1 |      1 |          0 |
|           2 |        1 |      2 |          0 |
|           3 |        1 |      3 |         -1 |
|           4 |        1 |      4 |         -1 |
|           5 |        1 |      5 |         -2 |
|           6 |        2 |      2 |          0 |
|           7 |        2 |      4 |         -1 |
|           8 |        3 |      5 |          0 |
7 rows in set (0.00 sec)

Source 1 is cable, 2 digital settop boxes, and 3 is a VCR. Cards 3
and 4 are in my computer room and only run a backend when needed.
Cards 1, 2 and 5 are available all the time.

For analog, It tries to use card 1 or 2 (coax) for everything and
only uses 3 or 4 if they are up and there is no other choice. Card
5 is only used if something can't fit on 1-4.

For digital, it tries to use card 2 (s-video) and would only need
card 4 if things couldn't fit on card 2. This never happens because
all the shows on premium and digital cable channels are repeated over
and over so they can always fit on the first digital input.

[Note to the other thread where they are talking about needing
three or four digital boxes. Wrong! ;-) I can record everything
I want to see from one box and watch the recordings from any of
four screens. My second cable box is essentially dormant and gets
most of it's use in testing.]

>> So, you could redo your cards and inputs so that "antenna" is first
>> but if the signal is actually better, I'd suggest leaving your card
>> setup as is and just setting the input preference to "1" so that it
>> will always try to get the clearest recordings for you. Way too much 
>> info is at: http://www.mythtv.org/docs/mythtv-HOWTO-11.html#ss11.7
> Since the PVR-150 is already the lowest input number perhaps I don't 
> need to define an input preference.  I'll have to do some testing.

I think you'll find that the cardinput you just added will lose to
the existing channels. If you want "antenna" to be the first choice
but you still prefer the earliest showing even if it is the channel
on the other source, you will need to re enter your card information
starting with the "antenna" input. However, start by testing the
input preference first. Less work, less drastic and I think you'll
find that it will be what you want in the long run.

If you want to change the input order, first backup your database
http://www.mythtv.org/docs/mythtv-HOWTO-22.html#ss22.5 . Run
mythtv-setup and clear card settings. Enter your sources in the
same order as before so that the sourceids and chanids will be
the same as before. Next, enter your "antenna" card and input
first followed by the other cards and inputs.

> Bruce, thanks a million for your detailed response.  This is very 
> helpful information.  Shuffling off now to read the howto....

I haven't updated it for a while so if something isn't currently
correct or is misleading, let me know so I can fix it.

--  bjm

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