Since some years I tinker with the perfect Home theater PC (HTPC) and finally I am pretty happy with my setup. I use a Zotac AD11 PLUS with an additional external HDD Raid1. For the actual sound I use the combination of a Denon AVR-X1000 with Teufel Consono 35 Mk3 5.1 speakers.
I use Ubuntu Server 14.04 LTS (trusty) on my Zotac AD11 (AMD E-450 CPU) and switched to the open source ATI radeon driver which now supports VDPAU. A post on the XBMC forum provides straightforward instructions to setup XBMC with the open source radeon driver and AMD 350/450 chipsets. I had to make two additional fixes. The opensource radeon driver does not support multichannel sound but supports pass-through of common dolby audio formats, so in order to upscale stereo sound – I relied on my Denon receiver instead of XBMC/pulseaudio. The second issue I had to solve was the constant loss of the HTPC’s HDMI signal on my TV, once I switched HDMI inputs on my Denon receiver to a different device (“no signal”).
In order to fix the HDMI issues I created a custom HDMI udev rule in:/etc/udev/rules.d/hdmi.rules To start a custom script upon HDMI signal changes: KERNEL=="card0", ACTION=="change", RUN+="/home/htpc/hdmi.sh"
The actual HDMI script simply uses xrandr to set the display output to HDMI-0.
#!/bin/bash
export XAUTHORITY=/home/htpc/.Xauthority
export DISPLAY=:0.0
xrandr --output HDMI-0 --auto