Originally Posted by undecided
I am sorry - but that is a myth that has been perpetuated based on one blog for many years. My connection was around 4 - 4.5Mbps for a long time and I had no problem getting the 720P HD streams on my BD390.
With the adaptive streaming it should adjust depending on the available bandwidth. As you can see from the Tomato streams it is downloading in in the 6 Mbps and then throttling back as needed.
Where is a (recent) Netflix statement saying you need 8Mbps for 1080P?
I am pretty sure when I see 5.2 Mbps 10 minute average downloads from the ROKU 2 I am getting 1080P/5.1 - but as you say there is no way to know for sure.....
It still needs headroom to maintain a buffer, and it needs to stay decently far ahead to insulate itself from the affects of fluctuation. The adaptive bit rate tech does not change that, it just minimizes the penalty of falling behind. Believe what you want, but I know people with 5 Mbps service who can only get the lower 2600 Kbps 720p stream, no matter what. Netflix has essentially repeated that much more recently than the 3 y/o "Encoding for streaming" blog entry in tweets on their Netflixhelps Twitter account about a year ago (see this
). Adaptive bit rate was definitely in use in many players back then and was always part of the installed PS3 player, the first to have access to 1080p encodings.
The Netflix player on the original Roku seemed to employ a strategy of filling its buffer to a particular level by bringing data down as fast as possible and then playing purely from the buffer for a while (about 30 seconds):
Most of those peaks are above 12 Mbps or greater; one of them is 18 Mbps (my guess is that with less available bandwidth the peaks would have been lower and fatter). Roku 2's Netflix player now reads from the net much more evenly and constantly; Roku 2's Amazon player still works like before.
If you have a PS3 or can borrow one, hook it up to your system and play an HD stream on Netflix, pressing the SEL button to get the little status display. If it hits and stays at "X-High/HD" then you're getting the 1080p encoding.
I've tweeted the following to Netflixhelps:
@Netflixhelps An old blog entry said that 40% headroom was required to get a given stream encoding; still true with adaptive bit rate?
If I get an answer, I'll post it.