[mythtv-users] Strange Playback behaviour

Andy Smith hastymind at googlemail.com
Tue Oct 9 12:39:14 UTC 2018


On Mon, 8 Oct 2018 at 15:27, Peter Bennett <pb.mythtv at gmail.com> wrote:
>
> The speed up and slow down problem is likely related to the audio. It
> tries to vary the video rate to keep in sync with audio. If it is
> getting bad audio timestamps or bad information from the audio driver
> this can happen. Run with -v playback and look at the log for
> confirmation. If this is the case I suggest trying different audio
> settings. Also there is a setting you can try. Run mythfrontend with -O
> AVSyncAveraging=60. The minimum and default value is 4. You can try
> different values. Higher values will smooth out the speed changes but
> may cause lip sync problems.

Thanks for the tip, I turned on the playback logging and here is a
link to part of the log during a couple of minutes of watching a
pre-recorded program. http://paste.ubuntu.com/p/4c6nPpYTwC/

Not sure what all these messages indicate, some, like this one :-

Oct  8 21:34:03 mustard mythfrontend.real: mythfrontend[18401]: W
CoreContext audio/audiooutputalsa.cpp:243 (IncPreallocBufferSize)
ALSA: Try to manually increase audio buffer with: echo 128 | sudo tee
/proc/asound/card1/pcm7p/sub0/prealloc

are obvious and I have attended to this now but not yet tested.
Others such as this one could be fixed (the device is owned by root
and mode 600) so that is where I was going to go next (1 step at a
time right ?)

Oct  8 21:34:05 mustard mythfrontend.real: mythfrontend[18401]: E
CoreContext vsync.cpp:358 (TryInit) VSYNC: RTCVideoSync: Could not
open /dev/rtc: #012#011#011#011eno: Permission denied (13)
-- 
Andy


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