[mythtv-users] how do I diagnose playback problems

[Paul]

I've got a intermittent playback issue which I see occasion Pauses 
and/or slightly out of sync audio. I've had this problem on MythTV 0.21 
and 0.22
I've changed my Video card from a Nvidia 8400 with 256Mb to a 512Mb ram.

Quality is good with VDPAU but  I get Prebuffering Pauses.. So I'm 
slowly going down the WAF scale...

is there a check list I can at least isolate where the problem is.., 
note I may even not be MythTV as I'm using the same box as a Firewall / 
router.


Can I assume if my audio is working that is ok?
I can turn on mythfrontend -v playback logging  but what if its some 
other performance issue with Linux how do I capture that?

Any help would be appreciated as I'm spinning my wheels going no-where 
at the moment

thanks