i use free bspayer build 817 (latest) and i noticed that the loading of mp4 files in bsplayer takes very long and sometimes also leads to that bsplayer freezes (meaning no buttons can be pushed anymore, has to be ended with task manager, but the playback continues fine)
this long loading happens independently of the used mp4 parser filter (i tried 3ivx and haali)
http://haali.cs.msu.ru/mkv/ http://www.3ivx.com/
the same files play fine on other dshow players like wmp and mpc