it's very likely that there could be a path problem (those where in my past). Check, whether your video resource is loaded correctly (by checking it within the browser or the access log). To verify whether your video code really works, try to use a very simple html page and get it there running.
Thanks for the answeer. It's clear it's not a path problem. But you have to know that even in a simple page without richfaces tag the video is not played. I really don't kno why. I repeat that I'm using richfaces 4 and I build I web site wich generate contenu via tinymce. I use the 3.x version so it's xhtml compatible. The reason I say there no path problem is because my picture are corectly displayed.