[mythtv-users] truncated recording

[Mark Wedel]

On 02/17/14 03:30 AM, Mike Perkins wrote:
> On 17/02/14 02:45, Mark Wedel wrote:
>>
>>   A few nights ago, my recording of OTA olympic recording was truncated.  It
>> would end after about 15 minutes.
>>
>>   Since I started watching it while it was still on, mythtv was claiming the
>> space used was increasing, and after it finished recording, statedthe recorded
>> size was about 25 GB.
>>
>>   However, using the info to find out the file name, and then finding the actual
>> file in the filesystem, it was about 1 GB.  Mythtv itself did not state any
>> errors with the recording.
>>
>>   There was plenty of space in the filesystem was was recording to (100+ GB), so
>> it is not a case of running out of space.  And my other large olympic recordings
>> have all been fine.
>>
>>   Any thoughts on cause or how to prevent this from happening in the future? I'm
>> more concerned about having this happen to other programs I'm not watching
>> immediately, and by the time I notice them shortened, it is too late to find
>> them on repeats.  Since mythtv seems to have believed everything went fine, it
>> wouldn't go and re-recorded such files.
>>
>>   Mythtv 0.26.1 on ubuntu
>>
> How long was your program? 1 Gb for an SD program works out at about half an
> hour. The average rate for SD is around 2Gb/hour, HD can vary according to the
> compression but can be around 8Gb/hour.

  Overall, I think the program would have been 3.5 hours or so.

  It was HD - and I did not look precisely how long the file was record, nor the 
precise size. It may have been closer to a 10 minute recording and 1.5 GB in 
size.  Though I don't think those precise measurements really have to do 
anything with the problem at hand.

>
> Since myth thinks the recording finished ok, and 25Gb sounds a more reasonable
> size than 1Gb for an Olympic session, perhaps you have a disk problem. Have you
> done any hard disk checks recently?

  There are no errors in the log messages or anything else to indicate a disk 
problem, though that isn't to say that might not be the cause.

  But in that case, I would expect that mythtv would see an error writing the 
data out, and thus not presume the file was recorded OK.  Mythtv clearly 
believed it was writing out data, yet the file itself does not reflect that.

  I could certainly believe that a bad sector/read after the fact may create 
this problem (mythtv is reading the data, gets an error, and ends playback). 
But the created file on the disk was only ~1 GB, so clearly at some point pretty 
early on, myth stopped writing to the file but did not indicate way.