When a video pauses to buffer seemingly forever, why does going back 5 seconds then forward 5 seconds load the video instantly?

Question

I’ve had Netflix or YouTube pause to buffer for 10+ seconds, I’d click the left arrow once and the right arrow once to rewind and then go back to where I was, then the video will start to play perfectly. Not sure why this is exactly.

In: Technology

Answer 1

Sometimes buffering is buffering, but sometimes buffering is retransmission. The TCP protocol has a variable delay retransmission mechanism to deal with network congestion. This is a great mechanism, as long as you don’t care about times when no data is transmitted. File transfer, email, even web browsing work great.

Alas, the Internet was not designed for streaming. This variable delay causes gaps in streaming. The player is just going to patiently wait, hoping that by not sending anything for a while, it won’t contribute to network congestion. Impatient users don’t like waiting, and they do things to restart the stream, even though this causes more congestion in the network overall.