i've actually had stuttering for the past few builds, but i figured I'd just wait to see the next release and thought it'd be fixed eventually. for me, it seems to happen with only mp4 files though, and certain ones at that. i've been testing it and it seems to be for my h264 and AAC encoded files. i forgot to put xbmc into debugging mode, but the regular log says this:
QUOTE
23:42:44 M: 49152 SEVERE: DLL: Q:\system\players\mplayer\mplayer.dll : malloc failed, crash imminent (Out of memory requesting 53544 bytes)
23:42:44 M: 49152 ERROR: mplayer generated exception in decode_audio
23:42:44 M: 49152 SEVERE: DLL: Q:\system\players\mplayer\mplayer.dll : malloc failed, crash imminent (Out of memory requesting 53544 bytes)
23:42:44 M: 49152 ERROR: mplayer generated exception in decode_audio
23:42:49 M: 32768 ERROR: exception in CApplication::FrameMove()
Look at the log. You're running out of memory i.e. malloc failed == cannot allocate memory. There's not enough processing power or memory to play high bitrate h.264 video. MP4 AVC takes horsepower to work.