Adaptive Streaming And Mother’s Day5/02/2011 12:01 AM Eastern
LAST WEEK, I POSTED A FACEBOOK
solicitation for glaze-over tech terms
worthy of translation. One slice of
jargon came in repeatedly: adaptive
So, Ron, Dawn, Ed, Jeff and John,
this is for you. And everyone else
who keeps bumping into the term.
Let’s start with the basics:
Adaptive streaming is the older sibling
of the “progressive download.” Both are terms
specific to moving and displaying online video to
screens attached to the Internet. (As opposed to
dedicated machinery for displaying video on TVs,
like set-top boxes.)
What’s “progressive” about the progressive
download is the buffering that happens along the
way to your screen and in the background. Remember
the early, early days of online video streaming
and the buffer indicator that drew itself in circles,
over and over, while the bits tried to get to your
screen? By progressively loading the video in the
background, we (gladly) see less of that these
Adaptive streaming takes it a step further.
What’s “adaptive” about it is its ability to throttle
down, or up, depending on available bandwidth.
Instead of one stream, of one size, loading into a
background buffer, the adaptive stream exists in
various sizes — small, medium and large, let’s say,
although some techniques slice it into 10 or more
sizes. It’s a mixture of traditional streaming, with
(This is why adaptive streaming tends to be
spoken synonymously with “fragmented MPEG-4,”
which also works by treating a video stream as a
series of small files.)
With adaptive streaming, the end screen — the
client — can sense the bandwidth on its connection
and send up a request for a “right-sized”
stream for what’s available. This way, the client
screen can switch between files on the fly, at varying
bit rates, depending on available bandwidth.
This is all great, unless of course you’re the
guy (hello, cable) who provisioned millions of customers
for, let’s say, 10 Megabits per second of
downstream throughput, on the assumption that
not everyone would use it all at once. Adaptive
streams of video tend to behave like a gas, filling
all available space.
With Mother’s Day coming up, it’s useful to
point out that the telephone network was originally
designed around that particular holiday, because
that’s when the most phone traffic occurs. The intent
was to minimize the occurrence of “all circuits
busy” on that peak calling day.
Think about it: On this Mother’s Day, will you
pick up the phone, or will you find a way to call
Mom so that you can see each other? Video is bigger
— way, way, way bigger — than voice. Adaptive
streaming helps that, for the end device. But it still
places a heavy load on available bandwidth.
Call your mother. She’ll be glad to hear from you
Stumped by gibberish? Visit Leslie Ellis at translation-please.com or multichannel.com/blog.