mplayer_1.0rc1-maemo.16 was released:
* Fix for aspect ratio problems on N800 for windowed video playback with xv video driver
* Workaround to prevent tearing and poor performance bug on N800 for 16:9 video files (https://maemo.org/bugzilla/show_bug.cgi?id=1281)
* Use floating point AAC decoder on N800 in order to support "Main" and "Sample-Rate Scalable" profiles. Problem with AAC codec was reported at http://www.internettablettalk.com/fo...ead.php?t=6061

The changes in this build primarily target N800 video output performance. In particular, tearing and slow performance for widescreen videos was solved.

Another quite noticeable performance improvement (20% improvement observed on Nokia_N800.avi video clip, for other files it may vary) requires installing xserver package with a patch for ARMv6 optimized color format conversion, two alternative links for download can be found here: http://maemo.org/pipermail/maemo-dev...ay/010058.html
Keep in mind that xserver is a critical system package and if anything gets wrong with it, you will probably have to reflash. Everything works fine for me, but you have been warned. Anyway, if you have videos which played not very smoothly before, you can try to check them now. If you like the results, don't forget to vote for https://maemo.org/bugzilla/show_bug.cgi?id=1278 (it would be nice to ensure that this optimization gets officially included into the next version of N800 firmware)

edit: Forgot to mention that optimized xserver will also improve performance for built-in video player and canola.