https://bugs.freedesktop.org/show_bug.cgi?id=76564
--- Comment #4 from jeroen jeroenk61@hotmail.com --- Sorry for not providing that information.
OpenELEC uses XBMC to play the videos. XBMC has the option to display stats (http://wiki.xbmc.org/?title=Codecinfo). One of the stats is the actual video frame rate. Other useful stats are the amount of frames dropped and skipped.
When I look at for example the numbers 23.95 and 23.92 it seems it is off by 1/1000 or 2/1000 respectively.