To Host or Not to Host?
Generally speaking, video streaming is more difficult than audio streaming. In turn, live video streaming is harder to accomplish than prerecorded Webcasts, also known as video-on-demand (VoD).
Depending on the type of content and the size of the audience, organizations can choose among self-hosting, third-party hosting, or split hosting options. In self-hosting, the organization hosts all of the content -- the launch site as well as the streaming content. Self-hosting can work out well for VoD implementations, analysts say.
For live streaming broadcasts, however, third-party or split hosting is often the preferred method for keeping the video and audio flowing more smoothly. In split hosting, the organization hosts the launch site only, redirecting requests for streaming content to a third-party server. In third-party hosting, the provider hosts the launch site and content alike.
"Live streaming doesn't necessarily add anything, though. In fact, VoD makes more sense for many applications. With VoD, you can pre-position a video on everyone's desk, so they can view it at their own convenience," observes Danny Sapir, CIO of Bandwiz, makers of the DistributeIt bandwidth management product.
Encoding -- Software or Hardware?
Streaming media entails three main steps: encoding, serving, and playback. Videoservers from vendors like Microsoft, RealNetworks, and Apple come with integrated software codecs for compressing and encoding source files. Videoservers are typically used with Web servers, which store and deliver the launch site data.
Most videoservers now enable multicasting, too, for spreading out the streaming media content load over multiple videoservers. Another advantage of multicasting? You can deliver selected content to designated groups of users.
Regardless of which platform you're using, there's probably a videoserver out there for you. Videoservers from RealNetworks and Apple supply extensive crossplatform support. RealNetworks' Helix Universal Server, for instance, will run on Windows NT/2000, Linux 2.2, Free BSD, Compaq Tru 64, Sun Solaris, HP-UX, or IBM AIX.
A free version of the Helix server, available for download over the Web, provides basic functionality. For more demanding applications, RealNetworks also sells Standard, Enterprise, Internet, and Mobile editions. Helix Universal Gateway, a product targeted at service providers, combines an Internet server with an integrated media cache for lowered bandwidth consumption.
For its part, Apple produces both QuickTime Streaming Server for the Mac OS X server platform and Darwin Streaming Server, an offering available in Linux, Solaris, and Windows NT/2000 flavors. Moreover, Darwin is billed as an open source server, tweakable for additional platforms, too, simply by modifying a few platform-specific source files.
As an alternative to software video servers, some vendors sell hardware-based encoders. Traditionally, software codecs have been better at handling lower bit rates, a particular advantage on lower-speed or highly congested networks. Hardware encoders, on the other hand, have tended to be a better choice in situations where video quality is a more important concern than bandwidth consumption.
VBrick Systems lets you make your own choice between hardware and software products. Ituner, a maker of Linux-based hardware encoders, recently started breaking down the media encoding, decoding, and server functions into separate boxes for even faster performance.
On the client end of the equation, PC-based media players from companies like Real Networks and Microsoft first buffer, or store, the digitized streaming media packets in the PC's computer memory. The packets are then decoded for desktop playback.