QT Pro on OS 9 will play more files, but not all. The mpeg file format is not simple, since the files can be compressed with many different compression schemes (codecs) and still be called an mpeg file.
If yo have access to OSX, the files can often be played by one of the following free players.
http://www.videolan.org/vlc/download-macosx.html
http://sourceforge.net/project/showf...group_id=62947