RadMediaPlayer supports smooth streaming since it uses MediaElement
internally. For basic scenarios you can use the BufferingTime
of RadMediaPlayer's MediaElement. BufferingTime is the time during which the video will be buffered before it is played.
// The video will buffer for 5 seconds before it gets played
radMediaPlayer1.MediaElement.BufferingTime = TimeSpan.FromSeconds(5);
For more advanced scenarios, you will have ti dig deep into IIS's SmoothStreaming
This is a tutorial that explains how to play smooth streaming video
the Telerik team