Playing HD content on Linux has not always been that easy to achieve. Firstly, you ideally need a supported graphics card and from my research it seems preferable to go with Nvidia over AMD/ATI for Linux supported drivers at the time of writing. Secondly, you will need to configure your system to make the best use of the hardware based decoder on the current generation of graphics cards. Here's how I configured Ubuntu 11.10, an Nvidia G210 / N210 and VLC to playback 720p and 1080i HD content on a lowly Intel Atom based system...
