Originally Posted by Suntan
That said, I know for a fact you can stream at less than 1500, and that you don't need 30% ahem headroom for streaming to all devices.
I'm fairly certain that they all need some
headroom (a pretty common engineering term), though maybe not all need 30%. The PS3, for instance, uses some very good adaptive bit rate tech; I doubt that it requires a huge amount of headroom to start streaming the next highest bit rate encoding because it can fairly quickly and seamlessly fall back to lower bit rate encodings if bandwidth available on the connection decreases. The players which have to do a lengthy rebuffer operation need the headroom.
Without any bandwidth headroom no buffer can accumulate and when bandwidth decreased a player would immediately have to stop playback and wait to buffer enough to continue.
Netflix streams are pretty damn variable rate as well, with very big bandwidth spikes. I monitored some in my router's realtime bandwidth usage display (see this
); I saw peaks of 13 Mbps in HD streams.