XBMC playback problems (mp4, mkv) after upgrade to Precise (12.04)

Expected behavior:

XBMC plays all supported video files correctly.

Actual behavior:

After upgrading to Precise (12.04) from Oneiric (11.10), XBMC stopped playing .mkv and .mp4 files correctly (and possibly others). .avi files seem to playback fine. Specifically, .mkv and .mp4 files start to playback, as I hear the audio just fine, but the video playback is not shown (i.e., completely black screen). Then, if I attempt to stop the playback, XBMC freezes, and the only way to correctly the problem is to switch to tty1 (i.e., press Ctrl-Alt-F1), login, and run 'pkill -9 -f xbmc.bin'.

Additional information:

Based on the information found at this URL:

    http://www.noobslab.com/2011/09/install-xbmc-on-ubuntu-1110-oneiric.html

I ran:

    sudo apt-add-repository ppa:nathan-renniewaldock/xbmc-stable
    sudo apt-get update
    sudo apt-get purge xbmc xbmc-bin
    sudo apt-get install xbmc

in order to try an alternate build of XBMC Eden (11.0). Doing so fixed all of the playback problems. Thus, I assume that the source of the problem concerns the Ubuntu build for Precise (12.04) rather than XBMC itself per se.

In order to check if perhaps the problem with the Ubuntu build was due to an upgrade issue, I ran the following:

    sudo rm /etc/apt/sources.list.d/nathan-renniewaldock-xbmc-stable-precise.list
    sudo apt-get update
    sudo apt-get purge xbmc xbmc-bin
    sudo apt-get install xbmc

in order to again completely purge XBMC from the system and install the official Ubuntu version. Unfortunately, doing so caused the described problems to occur again. Thus, I have switched back to the alternate build (i.e., from ppa:nathan-renniewaldock/xbmc-stable) and will keep this repo active until such time as this issue is resolved.

Thanks!

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xbmc 2:11.0~git20120423.cd20772-1
ProcVersionSignature: Ubuntu 3.2.0-24.38-generic 3.2.16
Uname: Linux 3.2.0-24-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Mon May 7 23:33:00 2012
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-color
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xbmc
UpgradeStatus: Upgraded to precise on 2012-05-06 (1 days ago)