A S t r e a m i n g M e d i a P r i m e r :
H O W D O I P U T M Y S T R E A M I N G M E D I A O N T H E W E B ?
HOW DO I PUT MY STREAMING MEDIA ON THE WEB?
A URL that begins with HTTP:// points to a Web server; a URL that begins with RTSP:// points to a streaming server.
Like any other resource fi le you publish on the Web, you post your media fi le to a server that has a con
nection to the Internet and an accessible IP address. Like any other resource fi le served over the Web,
your streaming media fi le is referenced by a URL (uniform resource locator). But there are some signifi
cant differences between publishing Web pages and downloadable fi les vs. publishing streaming media.
PUBLISHING STREAMING MEDIA
Web server vs. streaming server what's the difference?
Earlier in this primer, we distinguished between a Web server and a streaming server. Publishing your
streaming media fi les on a Web server is possible, but it results in pseudo streaming (aka progressive
download, aka HTTP streaming, aka fast start streaming in the QuickTime architecture). For true
streaming (aka hinted streaming in the QuickTime architecture), streaming media fi les must be posted
to a streaming server.
Are you absolutely, positively sure you want to do true streaming?
Web server pros
Web server cons
Streaming server pros
Streaming server cons
No special server software
Can't transmit live feeds
Only way to transmit live feeds
Requires a streaming server
needed; just use your Web server
Can't broadcast or multicast
Broadcasts and multicasts (one
Playback may be disrupted or
Media gets through no matter
No fl exibility for end user e.g.
stream to many viewers)
delayed if data rate exceeds
how slow the connection, because
end user cannot skip chapters
VOD (video on demand) fi les
connection speed or available
lost packets are retransmitted
audience must download fi le in its
can provide fl exible access
until they are received
entirety, from beginning to end
for end users
Media typically loses some data in
With fast connections, media
Leaves a copy of the media
Doesn't leave a copy of the movie
transmission, and lost packets are
plays as it downloads, so it seems
fi le on the end user's hard disk,
on the viewer's hard disk
gone for good
like streaming to the audience
risking unauthorized alteration
Does not use up space on end
Firewalls may not allow
End user gets to keep a copy of
user's hard disk
streaming fi les to pass
the fi le to play and/or share
Bandwidth usage can adjust
No problems with fi rewalls
What kind of streaming media server(s) do I need?
If you do not plan to stream too many fi les to very many people, and you can be sure that your entire
audience will be happy to use the same, single architecture, then you probably need only one server.
And it is possible to run your streaming server software on the same computer which is functioning
as your Web server.
But if your audience is large and you want to offer the opportunity for the end user to choose which
player to use, remember that you need a different streaming server for each architecture you plan to
support. To serve streams that are compatible with the three dominant architectures, you'll need server
software from Microsoft for Windows Media (.asf) fi les, from Real for RealMedia (.rm) fi les, and from
Apple for hinted QuickTime (.mov) fi les. What this means in terms of machines, is that you'll need
a Windows or Unix operating system to run all three servers, since Windows Media and RealMedia
servers do not run on MacOS.
In terms of hardware, the amount of storage you need can be calculated using the bandwidth math
basics you've already learned in this primer multiply the bit rate of your streaming media (in kilobits
per second) by the length of the media (in seconds) and divide by 8, to arrive at the amount of disk
space (in kilobytes) you need for your streaming media fi les:
(Kbps X seconds)