Flux can setup three different types of embedding. The first is HTML5 style, which is the modern, standards-compliant, recommended way of embedding.
The second is the 'Quicktime' style, which is a method recommended by Apple, and should be used with the 'Save for Web' feature in Quicktime Player. When using this method, choose the '.mov' variation of the movie.
The third is the 'OBJECT EMBED' style, which is older, less reliable, and should only be used when compatibilty with old browsers is required.
When embedding in the HTML5 style, you have the option of adding more media sources, for example, you could add an Ogg Theora alternative to a Quicktime movie.
At the time of writing, there is no media format that is supported across all popular browsers, this makes adding alternative sources very important.
As an alternative to multiple sources, you can as the 'html5media' Javascript library. This library will use a Flash based player to display the video when a browser is used that does not support any of the sources.
If this is the first time you have used this method on a page, you will need to add the required libraries to your page. Flux will do this for you if you click the checkbox.