chromeless-silverlight chromeless silverlight player in order to test smoothstreaming with mime type video/ism please add build line: echo adding tracingconfig.xml" to Player.xap "c:\Program Files\7-Zip\7z.exe" a $(TargetDir)Player.xap $(ProjectDir)TracingConfig.xml where TracingConfig.xml looks like: for more info see https://social.msdn.microsoft.com/Forums/windowsapps/en-US/7e1fa914-c062-41de-8712-b50eca31b2d9/cannot-find-file-tracingconfigxml-in-the-application-xap-package?forum=wpdevelop