video/mpeg plugin

I am looking for a mozilla/firefox plugin that plays video/mpeg, 
specifically MS mpeg4, embed file objects (as in "<embed src='xxyzz.mpg' 
/>") on the browser page.

 From https://pfs.mozilla.org/plugins/?application=mozilla

The only one that seems to play in the page, rather than spawn a 
separate viewer, is the quicktime plugin. The real player and windows 
media players seem to spawn their separate stand alone viewer.

However, the quicktime plugin seems to have problems with MS mpeg4.

Any suggestions?