[mythtv] Debugging mythfrontend video freeze

[Scott D. Davilla]

I'd like to get some help in debugging a frontend video freeze. I'm 
using svn version 14938 trunk builds. Setup is as follows;

backend:
	Dedicated backend w/ two PVR-150 and a dual channel 
HDHomeRun. So 4 encoders. This is all mpeg2 encoding. Backend has 
plenty of resources (core2 du0 at 1.83 GHz with four SATA 500GB 
drives for video storage and 320GB boot. Runs same svn version.

frontend:
	1GHz Pentium-M with nvidia 7300 for mpeg2 hardware decoding.


This setup works quite well in handling HD content from the 
HDHomeRun, video is nice and smooth and cpu percent is 60-70 when 
displaying 1080i or 720p ATSC HD content. The frontend has no problem 
displaying HD content besides the below problem.

The problem is I get random frontend hangs where the video freezes. 
Escape key works in that the frontend tells the backend it is done 
but frontend must be killed to fully recover as it's still hung 
somewhere. The freeze is very random, sometimes in minutes, sometimes 
hours. Smells like a race condition.

I've run full logs on both sides and there is no indication of any 
errors, I can see the last transfer request from the frontend, 
backend gets it and sends, frontend seems to get the transfer but 
there are no more transfer requests from the frontend. It's as if the 
frontend is waiting for something to complete. I am getting frontend 
prebuffering pauses but from what I can trace in the code, the 
frontend has run out of frames to feed to the decoder.

So I'm looking for a better understanding of the frontend process of 
getting video data from the backend, buffering and decoding, etc.. 
I'm viewing 1080i HD content from ATSC source. I can stick printfs 
and build and test but I'm looking a assistance in where to start 
looking and placing printouts so I can track this freeze down and fix 
it.

Thanks
Scott