The final solution for play mpeg2 file in powerpoint.

[wenxibo]

If you can play mpeg2 file in windows media player , you can play it in
powerpoint as well. But above all, you must confirm that the directshow
filter MPEG-2 Splitter has the higher merit than other mpeg demultiplex
filter, please see the detail at link:
http://www.easympeg.com/phpBB/viewtopic.php?t=5

You can use EasyMPEG MX or another tools to change the merit value of
MPEG-2 Splitter . in the DirectX 8 and after version, MPEG-2
Demultiplexer has the higher merit than MPEG-2 Splitter , this setting
will make the mplay32.exe failed to gather information of the file,
then it refused to play mpeg2 file.