[mythtv-users] NVP prebuffering pause

[Mark Hutchinson]

On 8-Feb-08, at 1:38 PM, Michael T. Dean wrote:

> 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
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users

This is interesting. I checked all of those settings and they are all  
good.
BUT, if I disable audio, by selecting NULL for the audio device, the  
SD picture is no longer jerky.

Here is my sound config ( I have tried standard PCI /dvv/pcm device  
too )
C-Media SPDIF out audio.  Configured with thwo two passthrough options  
checked and ALSA:default chosen.
I have a .asoundrc in place to enable the SPDIF.

Now, having sound disabled, really seems to fix it.  What could be  
happeining?
I also have a standard PCI Creative Audigy value card I could use if  
that would be easier to test with.

Perhaps we are on to a fix?

Mark