The Ins and Outs of Loading External Assets

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The Ins and Outs of Loading External Assets
When you load external assets into a movie, you're loading a media file (such as an MP3
file, a JPG graphic, a video, or even another SWF) into a Flash movie as it plays. In other
words, you're adding assets to your movie. In fact, you can create a Flash movie that
contains nothing but script set up to load text, animations, graphics, and sounds from
external assets. Media that's loaded dynamically in this fashion can exist on a Web server
or on a disk or CD if your project is distributed as a projector; therefore, a single project
can load media from several sources simultaneously. All that's usually required is the
directory path to the files. It's that simple! No special server technologies required.
Sometimes, as is the case when loading media files from a disk or CD, not even a server
is needed.
By loading external assets (rather than placing all of your project's media in a single
SWF), your project benefits in a number of ways:
•
Your movie downloads faster over the Web. Imagine that you have a site
containing four sections—Home, Services, Products, and Contact—each of which
has its own graphic and soundtrack. Together, the graphic and soundtrack add 100
KB to each section—a total of 400 KB if you place everything in a single SWF.
For users connecting via 56 Kbps modems, your site will take nearly two minutes
to download—a sure way to turn viewers away. You're better off loading each
section's graphic/soundtrack on an as-needed basis, or only when a user navigates
to that section—the approach that most HTML-based sites take.
•
You can view multiple movies in the player window without navigating to
different HTML pages. When using a browser to navigate Web sites, you don't
need to close one window and then open another just to move from page to page.

Instead, the browser remains open while the window's content changes as pages
are loaded and unloaded. The same thing happens when external movies are
loaded into Flash's player window: The player window simply acts as a container
whose contents (a Flash movie) change without the user having to close the movie
window or navigate to a different HTML page.
•
Your project becomes modular—and thus easy to update and reuse. When you
begin using assets loaded from external sources in your project, Flash movies
become nothing more than interactive modules that you can load (plug into) your
project at will. Any revisions to a particular module will appear automatically in
any other project that contains it. Think again of a standard Web site: Even though
each graphic (for example, a logo) usually resides in a single location on the
server, multiple pages can contain that logo simply by referencing its directory
path on the server—so you don't need to create a separate logo graphic for each
page. You can reuse that graphic on any number of pages, and all of the pages on
which it appears will reflect those changes anytime you update that graphic. The
same holds true for externally loaded content in your Flash projects—a benefit that
cannot be overemphasized because it's much easier to individually edit several
smaller, externally loaded files than to open a complex project with numerous
scenes, layers, tweens, movie clip instances, and scripting every time you need to
make a change.
•
Your project becomes more dynamic, offering each user a unique experience. By
loading external assets, you can provide the user with a much more dynamic
experience, employing a wider range of content that loads based on time of day,
month, user input, or even a randomly generated number.

Although it would be next to impossible to create a single SWF that could display
appropriate content based on so many variables, using externally loaded assets makes this
type of dynamic functionality a breeze.

You can load external assets by using loadMovie() or loadMovieNum() for external SWF
or JPG files, or loadSound() for external MP3s. Video assets can be loaded using an
instance of the netStream() class; however, the Media components provide a much easier
interface for getting video (and MP3) content into your project, as we'll discuss later in
this lesson.
In the following exercises, you'll learn how to load a variety of external file types, and
how to control these assets using ActionScript.

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