I might have an update to this. I've been experiencing hangs on some video streams (local disk and youtube), sometimes when I stop (x) and sometimes when the video comes to an end.
I'm running Arch Linux, and XBMC Gotham 13.1, however I've had hangs since a 12.x release.
I'm also using Pulse audio, but I'm running on Nvidia with the NVIDIA binary driver.
I run the xbmc-standalone binary, and it is the only X application running.
The most recent hang, froze on the last frame of the video, and the UI was totally unresponsive to keyboard commands.
I attached GDB to the running xbmc, and ran "thread apply all bt". The output is at
http://pastebin.com/qYLhEysB
When I quit the debugger, XBMC miraculously unfroze, and seemed to be working again just fine.
The output from my xbmc.log at this time is at
http://pastebin.com/caiLXDme
XBMC froze at 19:44:22.
I detached the debugger at 20:26:12.
Hopefully this can be useful. I unfortunately did not have XBMC running in debug mode. I'm running just the standard archlinux PKGBUILD from the main repos.
I'm happy to try more debugging with whatever options someone would like to track this annoying issue down. I typically have it happen about once a day.