To gain some insight into prefetching, let’s take a look at a simple example.
Suppose the video consumption rate is 1 Mbps but the network is capable of delivering
the video from server to client at a constant rate of 1.5 Mbps. Then the client
will not only be able to play out the video with a very small playout delay, but will
also be able to increase the amount of buffered video data by 500 Kbits every
second. In this manner, if in the future the client receives data at a rate of less than 1
Mbps for a brief period of time, the client will be able to continue to provide continuous
playback due to the reserve in its buffer. [Wang 2008] shows that when the
average TCP throughput is roughly twice the media bit rate, streaming over TCP
results in minimal starvation and low buffering delays