[mythtv-users] Blank Recordings - please confirm

Chris K ckotting at wideopenwest.com
Wed Nov 30 20:12:25 EST 2005


When we left our saga, I had promised to check out raising the priority 
of Tuner0 over that of S-Video0 to see if that resolved the issue, and 
report back.  The answer is: "It does!"

What I >suspect< happens is that, just as the backend selects a 
/dev/videoN (i.e. capture card) from a number of /dev/videoNs of equal 
priority based on their order in the list of tuners (okay, not really, 
but bear with me for the sake of a brief explanation), it selects an 
input from all of the active inputs on a given /dev/videoN based on 
their order in the list of inputs presented in mythtvsetup.

If you have both S-Video0 and Tuner0 configured and operational, it will 
record from S-Video0 because it appears first in the list.  However the 
"Input Preference" (actually, as someone else commented, "priority" 
would be a better term) overrides this, and the input with the higher 
priority takes precedence for recording (again, just as the /dev/videoN 
whose input has a higher preference is selected).

SO it appears that, if you want or need to have multiple inputs 
connected and configured on a single capture card, you can select one of 
the inputs for off-air recordings by raising its preference over other 
inputs on that capture card.

Again, this is all suspicion, as I haven't yet delved into the code, but 
based on my tests this evening, it seems to work.

Chris K.


David Watkins had the sense to say...

>Date: Wed, 30 Nov 2005 13:38:52 +0000
>From: David Watkins <watkinshome at gmail.com>
>Subject: Re: [mythtv-users] Blank Recordings - please confirm
>To: Discussion about mythtv <mythtv-users at mythtv.org>
>Message-ID: <44829edd0511300538y62995258s at mail.gmail.com>
>Content-Type: text/plain; charset=ISO-8859-1
>
>I think your problem might be having the guide data on the SVideo
>input.  Myth is going to think that it can use that channel for
>recording (maybe the blank recordings are from the VCR while it was
>turned off?).
>
>If you only want to capture from VCR then you're better off with no
>guide data and using manual recording.
>
>If you want to use your VCR as a tuner then I think you'll need a
>channel change script.  Even if you intend to set the VCR channel
>manually I believe that a 'dummy' script that does nothing, but
>returns successfully, is needed to convince myth that it has selected
>the correct VCR channel.
>
>As you say, you'll also need a way to disable recording on the SVideo
>input when you haven't got the VCR turned on and tuned, and I don't
>know how to do that, but increasing the priority of the tuner over the
>S-Video should help.
>

On 30/11/05, CHRIS KOTTING <ckotting at wideopenwest.com> wrote:

>> I'm having an issue with blank recordings, and I wanted to confirm what I'm
>> finding by searching the archive (because I'm hoping that there is a
>> different answer available).
>>
>> I have two inputs to a PVR-150 card connected, Tuner0 goes to my cable (no
>> cable box) and the S-Video input comes from our VCR.  Both are configured in
>> mythtvsetup, each with its own channel line-up.  The connection to the VCR
>> is primarily for pulling our home videos into Myth, but I was hoping to be
>> able to use the VCR as a second tuner, and be able to switch between two
>> channels by using "C" to change inputs.  (Yes, I know this would play hob
>> with the ringbuffer, so maybe it's a silly idea.)
>>
>> Anyway, since I set up the S-video input, scheduled recordings have all been
>> blank.  The files are there, and I didn't see any problems in the logfiles
>> when I looked at them.  (Can't append them right now, as I'm nowhere near
>> the machine, and have no way of ssh-ing to it.)
>>
>> Is it (still) true that you cannot have two different inputs configured in
>> mythtvsetup and record reliably?  I was wondering if this could be gotten
>> around by raising the priority of Tuner0.
>  
>



More information about the mythtv-users mailing list