Although is recommended using a dedicated media center distribution (raspbmc, openelec or xbian for example) because they come already configured, if you decide to install XBMC on your own in Raspbian you may have problems playing videos. If you don’t see video and it just plays the audio when opening a movie it may be caused because XBMC is trying to use hardware acceleration and you don’t have the MPEG-2 license in your Raspberry Pi.
To use software decoding follow those steps:
- Go to System -> Settings and then select the “Video” tab.
- Change the “Settings level” in the lower left corner to “Expert”. This will reveal the “Acceleration” menu option.
- Now go to the “Acceleration” menu option and change “Decoding method” to “Software”.
You can see a video doing those steps here.
If this doesn’t fix the problem by itself try adding this option to /boot/config.txt:
start_x=1
This enables the use of “_x” firmware files and should allow software codecs to work.