Hi! I have made a site that has a video but it is impossible for viewers to watch it if thae brouser(mosilla, opera) doesn't have the necessary plug-in. How can I install the plug-in in the server to fix it and what plug-in do I need?

thank you very much

http://reference.sitepoint.com/html/embed/pluginspage

and what plug-in do I need

That's best known to you!

You made the video.