[mythtv-users] mythbackend missing recordings.

Michael T. Dean mtdean at thirdcontact.com
Mon May 25 18:09:33 UTC 2009


On 05/25/2009 12:44 PM, Tom Dexter wrote:
> On Mon, May 25, 2009 at 10:31 AM, Michael T. Dean wrote:
>   
>> On 05/25/2009 10:21 AM, Glenn Sommer wrote:
>>     
>>> Yes, all permissions are correct.
>>> btw, I was wrong in my statement about 0byte files, actually it
>>> doesn't even create the files at all.
>>>
>>> Anyway, I've tried raising the tuning timeouts for both DVB-C cards...
>>> Maybe that will make a difference...
>>> Though, if the backend timeouts when tuning - doesn't it retry later then?
>>>       
>> If you get no file at all (and no reported errors in the backend log file),
>> that generally means that the capture card did not provide /any/ data at all
>> for MythTV to write.  (Note that this is assuming you have permission to
>> write to the recordings directories--if you don't, there should be an error
>> in the logs and it should show that it stopped trying to record early rather
>> than showing a message saying it's stopping the recording at the proper
>> time.)
>>
>> So, sounds like a capture card/driver/configuration issue.
> Hmmm...when we discussed missed recordings here:
>
> http://www.gossamer-threads.com/lists/mythtv/users/361585
>
> I wasn't aware of what you're saying above.  The missed recording
> thing has happened to me on rare occasions, but I'm almost certain
> that when it did, I too got no recording at all with no errors in the
> log...not a zero length file.
>
> In my case this was DVB-T recordings with properly configured HD-5500
> cards using fairly current kernel drivers.  When it's happened it's
> sometimes been with more than one show in a row on the same station,
> and even with different cards of the three HD-5500s I have.
>
> Especially give how rare it is, it's hard to imagine that being a
> configuration issue.  If/when it happens to me again, I'll make sure
> to check if it's zero length or missing, but I'm all but certain they
> were in fact missing altogether.  It seems to me that the same has
> been true for others who've had this occur.

IIRC, when my local CBS affiliate (channel 6_1) changed frequencies of 
its digital transmission (completely unscheduled thanks to the 
government's last-minute decision to make the transition a "soft" 
deadline--they've just been putting up a "we recommend you rescan 
frequently" message), I got no recording files for all the shows on that 
channel (of course) but there were no errors in the mythtv logs.  
Instead, the errors showed up in the system logs.

However, the interesting thing was that with the HD-3000 I was using, 
the effect was to not only miss the recordings on channel 6_1 in this 
way, but /also/ the recording that followed that recording (regardless 
of channel).  Trying to record from the frequency without the 
transmission somehow put the card/drivers into a state that prevented 
the next recording from working, too.

A friend who's running Myth with the same OTA HDTV setup, but using the 
Avermedia A-180, only lost the 6_1 recordings.  His card didn't get into 
a bad state after the recording on the broken channel.

However, since you're using the HD-5500, I wouldn't be surprised if it 
has the same issue as the HD-3000.  Since you don't seem to be missing a 
lot of recordings, I'm guessing that if this is your problem, the broken 
channel is an infrequently-used channel.

So, my recommendation is to wipe your video source ( 
http://www.gossamer-threads.com/lists/mythtv/users/264034#264034 --just 
the video source portion, not the capture card portion) and then do a 
full rescan.  You can try just rescanning without first clearing things, 
but the best way to ensure this is not your problem is to start from a 
known (empty configuration) state and reconfigure the channels from scratch.

Mike


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