Enabling overlay for Intel graphics on Ubuntu

For Ubuntu Karmic and Lucid one needs to install a new kernel (e.g. 2.6.33) and current xorg packages, see here.

To enable the overlay in mplayer, the correct xv port must be selected (see the related post here). Check available ports: xvinfo | grep -B 2 "port base"

Run mplayer accordingly, e.g. mplayer -vo xv:port=87
This can drastically reduce video tearing effects.