[mythtv-users] NVP prebuffering pause

[Michael T. Dean]

On 02/08/2008 03:31 PM, Mark Hutchinson wrote:
> On 8-Feb-08, at 1:26 PM, Michael T. Dean wrote:
>> On 02/08/2008 11:21 AM, Mark Hutchinson wrote:
>>     
>>> What does this mean exactly?
>>> I have this in the mythfrontend log
>>> I get SD jitter whenever this appears.
>>>
>>> Firewire capture from DCT6200.
>>> I have tried all setting on render and deinterlace but still get  
>>> this.
>>>       
>> It means Myth can't read the data fast enough to display it in real
>> time.  Could be I/O issues reading the recording.  Could be due to
>> network latency/bandwidth (i.e. wifi is bad for Myth--OK, that's a
>> simplification, but not a bad one, IMHO), SQL issues, ...
> OK, a bit more info perhaps would assist.
>
> It is all local, no NFS, 80 gig SATA drive, I see no real IO wait, 4  
> gigs ram, Core2duo 1.86 ghz ( too slow you think ) and I dont see much  
> load on the cpu.
>
> What might I try?  SQL?
> Thanks for the help.

Could be audio issues.  If your audio configuration is wrong (which is 
quite possible since generally SDTV and HDTV have different audio types 
and handle audio differently),

As a first step, make sure you have (left) enabled:

Extra audio buffering
Enable this setting if MythTV is playing "crackly" audio and you are 
using hardware encoding. This setting will have no effect on MPEG-4 or 
RTJPEG video. MythTV will keep extra audio data in its internal buffers 
to workaround this bug.

(i.e. the default is for that to be enabled, so make sure you haven't 
disabled it).

And don't enable:

Use video as timebase
Use the video as the timebase and warp the audio to keep it in sync. 
(Experimental)

If that doesn't help and it is an audio issue, it's almost definitely 
not the Myth configuration, but your ALSA configuration or whatever.

But, then again, it may not be an audio issue.  Unfortunately, NVP 
prebuffering pauses can be caused by a huge range of different 
configuration issues.

Mike