As you can expect, there is no single file format for Web video. While the
situation isn't as bad as it is for graphics (with literally hundreds of
types), there are two major video formats used for Webcasts. The first is
RealVideo from Real Networks, which is the de-facto standard for online video.
RealVideo is a well-developed format that is designed especially for streaming.
It offers superior picture quality over different connection speeds. The other
is the Windows Video from Microsoft that apes many of the features of
RealVideo.
Three older formats, which were around during the early days of the Web, are
also used for Webcasts. These formats are MPEG, AVI, and Apple QuickTime. MPEG,
AVI, and QuickTime files are larger than RealVideo and Microsoft formats. If
you add sound to the files, you'll see their sizes balloon dramatically.
Viewing Webcasts
Viewing Webcasts is easy. You simply have to point and click a link with
your mouse. Once you click the link, the software that plays the video format
being used by the site opens. After a delay of a few seconds or so, the show
starts.
Of course, all of this doesn’t work without the proper software, called a media
player. To play RealVideo, you need the RealPlayer. This is a freeware
application for Windows, the MacOS, and Linux. There’s also a version available
for $29.95 (U.S.)
that contains a few features lacking in its free counterpart, including
powerful full-screen video capabilities. You can view Webcasts in Microsoft’s
streaming video format using the Media Player that comes bundled with Windows.
Media Player can also open AVI files, and you can download a QuickTime player
from Apple's Web site.
Some sites, like the Cable News Network and the BBC, do away with the need
for launching a separate viewer. They embed the video in a Web page and play it
on the page. The content of the Webcast appears as a graphic would, but with
controls for playing, stopping, and rewinding the video. However, you still
need the appropriate viewer installed on your computer.