http://blogs.msdn.com/b/randyoakley/archive/2010/06/21/what-s-new-in-expression-encoder-4-player-templates.aspxThe Expression Encoder 4 player templates have had the following major updates since Expression Encoder 3 Converted to Silverlight 4 Replaced use of Expression Encoder Smooth Streaming Media Stream Source with the IIS Client Team's "SmoothStreamingMediaElementen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)