Graphics Programs Reference
In-Depth Information
play, and sometimes a warning appears telling the user that the download is being inter-
rupted. Any of these things can be annoying and cause the user to leave the page without
viewing the entire video clip.
Web sites that include digital video use several solutions to minimize playback inter-
ruptions and maximize the user's viewing experience. These solutions include multiple
clip options, multiple formats, and specialized video servers. By offering the same digital
video clip in multiple fi le sizes, a site can satisfy a wide range of visitors. Sites taking this
approach often offer each clip in low, medium, and high resolutions. They sometimes
instead offer dial-up and broadband sizes, which means that they have used the compres-
sion parameters discussed earlier to offer the same clip in a lower-quality/smaller-frame
size for users with slower dial-up connections and in a higher-quality/larger-frame size
for users with faster broadband connections. Some sites also offer different format options
because some users prefer the QuickTime format and player, whereas others might
choose RealMedia, Flash video, or Windows Media. In addition, bigger-budget Web sites
might use a specialized video server to monitor a user's connection and adjust the video
quality to compensate for slowdowns, increasing the likelihood that the user can view
the video clip without interruption. Another benefi t provided by a video server is the abil-
ity to allow thousands of users to view the same clip simultaneously, which is impossible
when including video on a standard Web server.
The second method of including video in Web sites is through video fi les. Video fi les
are created or recorded with programs outside of Dreamweaver, such as Avid, Apple
Final Cut, and Adobe Premiere, and can be added to Web pages in Dreamweaver.
Choosing When to Include Video in a Site
Video can add excitement to a Web page and greatly enhance the experience of site visi-
tors. However, even with compression, video files are relatively large and might be slow
to download, especially for users who have dial-up connections. Because video includes
moving images and often sound, it requires more focused attention from site visitors.
This can be both good and bad. Video can really reinforce what you are trying to say and
users tend to pay attention, so it is a good way to drive home an important message.
But, it is easy to overload users with too many messages or too much motion in a page.
Video then becomes a distraction and can detract from the site's effectiveness rather
than reinforce it. Because of the steeper user requirements (more time to download and
more focused attention from the user), include video in a site only when it is truly appro-
priate for the site goals and the target audience.
When deciding whether to use video in a site, keep in mind that when site visitors
must wait for something large to download, their expectations are raised. Or, put another
way, site visitors wait for downloads only when they perceive that the content is some-
thing worth waiting for.
As with other media elements, assistive devices usually cannot interpret video con-
tent. This means that video content will not be accessible to users who require these
devices. Because of this, do not use video as the primary source to convey important
information. Instead, use video to augment the accessible content in your site.
Reviewing Video File Formats
Digital video can have many different formats. Most of the popular sound formats can
also be used for video, including RealMedia, QuickTime, Flash, and Windows Media.
As with audio formats, earlier versions of these video formats were preferred for different
uses. Although differences still exist, all of these formats provide excellent video perfor-
mance with a wide range of materials. Today, Web sites that include video often offer the
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