[mythtv-users] 0.27 watching Live recording freezes

Dave Hill myth at davidrhill.com
Sat Nov 23 15:29:50 UTC 2013


On 11/20/2013 11:21 AM, Steven Adeff wrote:
> On Sun, Nov 17, 2013 at 9:04 PM, Dave Hill <myth at davidrhill.com> wrote:
>> Hello,
>> I'm running the Mythbuntu 12.04 with the latest 0.27-fixes.  My backend is a
>> dual-core phenom II w/4GB ram and the recordings are in their own 1.5TB
>> partition with 100GB kept free.  It has a HDPVR for recording from my STB.
>> My frontend is a nvidia ION system with the recordings partition mounted
>> over NFS (not sure if that is relevant).  I generally do not have any
>> problems with this setup other than this.
>>
>> I have been seeing this problem primarily when watching NFL football games
>> on Sundays.  It only happens if the recording is in progress. It doesn't
>> seem to matter if I am watching 2 hours or 5 minutes or 30 seconds  behind
>> the current time.  The picture freezes during playback and eventually exits
>> with video frame buffering failure. When it happens, it continues to happen
>> after I restart playback, perhaps with 2-10 minutes of playtime between
>> freezes.  Rebooting the frontend machine has worked most of the time, though
>> in one instance, I needed to reboot the backend as well to clear it up.
>>
>> At the time of the failure, I see this in the mythfrontend log:
>>
>> Nov 17 17:54:48 dhliv mythfrontend.real: mythfrontend[6857]: I Decoder
>> ringbuffe
>> r.cpp:1098 (WaitForAvail)
>> RingBuf(/storage/recordings/2786_20131117212400.mpg):
>> Waited 0.2 seconds for data #012#011#011#011to become available... 0 < 32768
>> Nov 17 17:54:48 dhliv mythfrontend.real: mythfrontend[6857]: N CoreContext
>> mythp
>> layer.cpp:2130 (PrebufferEnoughFrames) Player(l): Waited 102ms for video
>> buffers
>>   AAAAAAAAAAAAALff
>>
>> ... then a bunch of similar messages with the "waited" time ticking up till
>> it reaches 20 seconds:
>>
>> Nov 17 17:55:08 dhliv mythfrontend.real: mythfrontend[6857]: N CoreContext
>> mythp
>> layer.cpp:2130 (PrebufferEnoughFrames) Player(l): Waited 19932ms for video
>> buffe
>> rs AAAAAAAAAAAAALff
>> Nov 17 17:55:08 dhliv mythfrontend.real: mythfrontend[6857]: E CoreContext
>> mythp
>> layer.cpp:2153 (PrebufferEnoughFrames) Player(l): Waited too long for
>> decoder to
>>   fill video buffers. Exiting..
>> Nov 17 17:55:08 dhliv mythfrontend.real: mythfrontend[6857]: I CoreContext
>> tv_pl
>> ay.cpp:2198 (HandleStateChange) TV: Attempting to change from
>> WatchingRecording
>> to None
>>
>>
>> In the mythbackend log around the same time, I see this:
>>
>> Nov 17 17:52:14 davetv mythbackend: mythbackend[2199]: I ProcessRequest
>> recorder
>> s/recorderbase.cpp:457 (GetKeyframeDurations) RecBase[5](/dev/video5):
>> GetKeyfra
>> meDurations(308350,9223372036854775807,#65) out of 2475
>> Nov 17 17:52:43 davetv mythbackend: mythbackend[2199]: N Expire
>> autoexpire.cpp:2
>> 64 (CalcParams) AutoExpire: CalcParams(): Max required Free Space: 82.0 GB
>> w/fre
>> q: 15 min
>> Nov 17 17:54:30 davetv mythbackend: mythbackend[2199]: E ProcessRequest
>> programinfo.cpp:2358 (GetPlaybackURL) ProgramInfo(2705_20131028005900.mpg):
>> GetPlaybackURL: '2705_20131028005900.mpg' should be local, but it can not be
>> found.
>> Nov 17 17:54:30 davetv mythbackend: mythbackend[2199]: I
>> PreviewGeneratorQueue mythdbcon.cpp:409 (PurgeIdleConnections) New DB
>> connection, total: 15
>> Nov 17 17:55:43 davetv mythbackend: mythbackend[2199]: I ProcessRequest
>> mainserver.cpp:1420 (HandleAnnounce) MainServer::ANN Playback
>> Nov 17 17:55:43 davetv mythbackend: mythbackend[2199]: I ProcessRequest
>> mainserver.cpp:1422 (HandleAnnounce) adding: dhliv as a client (events: 0)
>>
>>
>> Watching 'top' during the failure on the backend, I see that it is showing
>> 10-15% idle time, with 100% of one of the cores being used by mythcommflag.
>>
>> Does anyone else have similar problems?  What other information should I
>> gather to help diagnose it?
>>
>> Thank you,
>> Dave Hill
> every so often this will happen, but simply starting the recording
> again will allow for many more hours of livetv viewing without issue.
>
> what does the wait i/o look like when this happens?
> I agree, NFS may be at issue.
>
RE: 'simply starting the recording again'... I have tried restarting 
playback of the recording many times and it keeps freezing.  Are you 
saying I should stop recording the program and restart it?   It seems 
like stopping commflagging was enough to make it playback smoothly, so I 
think that will be my workaround for now.
What command would I use to check the wait i/o?
Could this be the result of too many capture cards with only one storage 
group?  My backend has 1 HDPVR + 2 HVR2000s and 1 PVR150 and they all 
record to one storage group.  Perhaps the load of a couple of HD 
recordings + both commflagging + 1 frontend watching is too much for the 
hard drive?  I am considering adding a storage group on a new drive to 
see if that helps.

Thanks,
Dave



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