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HOW DOES STREAMING WORK?
SERVERS WITH A SMILE?
Although streaming technology can start to seem mighty complex mighty fast, it's all
really based on this simple model:
If you are a do it yourselfer who is not
going to be streaming very much media
to very many people, your Web server
The end user selects
The Web server relays the
and media server might just be different
a media fi le, causing
request to the media server.
processes (handled by different server
software applications) running on
a request to be sent
the same machine.
to the Web server.
If you are already going into techno
phobic shock at the very mention of
clients and servers, don't despair,
read on The techies who invent these
things love to confuse the rest of
us with tricky terminology, just to
The Media server
make sure we keep them around.
streams the media fi le
While the term server sometimes
back to the end user's computer.
refers to hardware, as in That old server
The client, or player, decodes
is collecting dust, it may also mean
and plays back the media fi le.
software, as in We installed a new Web
server on that computer today. Both
uses actually refer to the same princi
WHERE DO STREAMS COME FROM?
ple a server is a solution designed to
receive requests from a third party and
respond by delivering, or serving up,
Streaming media architectures
a particular type of data. This process
An architecture is an interdependent system comprised of a variety
is also known as a transaction.
of components that all work together to perform certain functions.
Requests are sent to a server by a client.
Streaming media architectures are comprised of encoding and trans
Again, the term client may be used to
mission methods, server software, and players (client software).
refer to a PC (hardware) or to a software
Currently, the three most popular streaming media architectures
application. A good example of a client is
are RealMedia, Windows Media, and QuickTime.
a Web browser, which is software installed
on a PC that functions as a client to Web
There are also a few interesting alternatives available, including archi
servers. When the client receives the data
tectures based on Java applets that do not require the end user to have
it has requested from the server, it may
a proprietary player (or plug in) installed. Instead, an ultra light Java
further process and/or display the data.
applet delivers an ephemeral player to the end user's browser, enabling
Media players are software clients that
playback for the duration of the streaming session, after which the
process and play back video and/or audio.
player is discarded. While such java based players are usually less intru
Any computer on which the appropriate
sive than proprietary players some even virtually transparent they
server software has been installed can
typically do not offer the full range of end user controls made available
function as a server. But typically, when
by the proprietary players.
a piece of hardware is dedicated to
that role, it is made up of high grade
Currently, however, and for a variety of technology and business reasons which
components that will deliver reliable
are beyond the scope of this document, the streaming market is dominated by three
architectures: RealMedia, Windows Media, and QuickTime. The unfortunate result is
that there are now three parallel standards that do not work together. Imagine what it
If you reach the point where you are
serving so many streams to so many users
might have been like if, when television fi rst hit the airwaves, each of the three major
that, in order to handle the traffi c, you
networks required a different device to translate their signal into video and audio each
need a dedicated media server (and you
home would have needed an ABC television set, a CBS television set, and an NBC televi
namic Medianamic Media
decide to handle your media hosting in
sion set, if the household wanted to watch programs on every channel. That's essentially
house rather than outsourcing), you will
what the situation is, in today's streaming media marketplace. While there is some
probably want what is known as an
limited cross over in the players' ability to play back other architectures' formats, the
appliance server or network appliance.
technology is so competitive, that end users cannot count on cross over capabilities
A network appliance is server hardware
obe Dobe D
working, as the formats rapidly evolve. This can be confusing and irritating for end
with factory installed server software,
users, who must continually download the latest plug ins and then fi gure out which
designed specifi cally for a specifi c type of
server function such as handling media.
to choose as the default player in their browser, based on which is being supported
by the majority of their favorite content providers.