if you want play mp4 files in BSPlayer download this
http://www.free-codecs.com/download/MP4_Splitter.htm
1. Unarchive the package and use the files from Release folder if you're running Windows 9x/Me or Release Unicode if you're running Windows 2000/XP.
2. Copy DLL or AX files in system32 folder [ C:\WINDOWS\system32 ]
3. Click on Start > Run...
• To install the files, type: regsvr32 filename.dll or regsvr32 filename.ax
• To uninstall the files, use: regsvr32 -u filename.dll or regsvr32 -u filename.ax