They're probably using DASH[1]. The video is split into several segments and therefore the player will fill the bufer only until the end of the current segment.

They're probably using DASH[1]. The video is split into several segments and therefore the player will fill the bufer only until the end of the current segment. Below each codeschool video you have a download link, so you can view them offline. [1]: http://en.wikipedia.org/wiki/Dynamic_Adaptive_Streaming_over_HTTP http://en.wikipedia.org/wiki/Dynamic_Adaptive_Streaming_over...