 | Designing Web Audio |  |
Two of the most popular tools for delivering interactive multimedia on the Web are Macromedia Flash and Shockwave. Both technologies offer superior control over multimedia creation and playback across various browsers and platforms. If you are developing interactive content with motion graphics and sound, using Flash and Shockwave should be your first choice.
While RealAudio was instrumental in bringing the radio broadcasting experience to the Web, Macromedia's influence on interactive media began with the launch of Shockwave in 1995, a technology that converted Macromedia Director presentations into a compressed format for web delivery. About a year after Shockwave's release, Macromedia acquired the technology that has become Flash, which uses efficient vector graphics and compressed audio to create web multimedia. While the two tools have some similar capabilities, they're aimed at different types of projects. Shockwave takes advantage of Director's scripting language, Lingo, to create complex presentations and games. Flash, on the other hand, is handy for simple button rollovers, presentations with basic branching logic, and situations where download speed is critical. Both formats provide the software components and authoring capabilities necessary to build advanced interactive soundtracks and customized media.
Flash and Shockwave allow you to create an immersive multimedia experience on your web site. Despite the introduction of RealSystem G2 and SMIL, we found that Flash and Shockwave formats still provide more creative, high-impact multimedia works.
At the core of Shockwave and Flash multimedia lies a sophisticated authoring environment that exports various media elements into one compressed binary movie file. Using a standalone authoring environment to produce a self-contained media file has many advantages over text-based markup language media formats such as SMIL and Java. For example, the synchronization and playback of complex Shockwave and Flash presentations is more reliable than SMIL-based media. More important, the overall level of interaction between media elements is much more advanced in Flash and Shockwave than in text-based formats.
Although Shockwave was heavily promoted, it is not as ubiquitous on web sites as RealAudio or Flash because of its large plug-in size and higher bandwidth requirements. What Shockwave does best is create rich CD-ROM-like interactive multimedia. However, the result is often a download that is too slow over 56 Kbps modem connections. While Shockwave is a great multimedia-authoring environment, its bandwidth-hungry video and audio are best experienced with the throughput of xDSL or at least a T1 line. However, if you are careful with preloading and streaming, you can successfully create interesting Shockwave media suitable for modem users. The Enigma III Shockwave mixer, discussed later in this chapter, provides a good example of how you can create engaging Shockwave media over limited bandwidths.
Flash and Shockwave
Originally developed by FutureWave Software as the FutureSplash Animator, Flash utilizes vector-based technology to deliver interactive real-time animation and sound over standard modem speeds. And with the addition of ActionScript in Flash 4, Flash pieces can offer more advanced interactivity.
Shockwave for Director is a software component that enables compatible browsers such as Netscape Navigator and Microsoft Internet Explorer 2 and up to play Director movies over the Web. Shockwave is designed to work with standard HTTP servers and is ideal for streaming short- to medium-length audio clips and for scripting more advanced multimedia presentations and games with Lingo.
Flash has gained a broad following, with its stripped-down and simplified authoring environment, small plug-in sizes, and low-bandwidth-friendly vector animation. Flash-based multimedia web sites are great for product or service demos, educational tutorials, targeted branding campaigns, and promotions that call for a high-impact, media-rich viewing experience. Flash also works well embedded as a small animation window in a standard text and graphics-based HTML page.
If a user does not have the Flash plug-in, you can use Macromedia's Aftershock utility to easily generate the HTML and JavaScript to automatically replace the Flash movie window with a static GIF image (see Figure 9-1). The Aftershock utility is a key breakthrough for web developers because it addresses their trepidation over implementing plug-in-dependent media on a high-traffic web site. The Aftershock utility also works with Shockwave. Aftershock is a free utility available on the Macromedia web site at http://www.macromedia.com.
Flash and Shockwave are designed to be served from a standard HTTP web server like the rest of your web site content. On the upside, Flash and Shockwave content is easy to broadcast because you do not need to install special server software; the downside is that you do not have the benefits that dedicated server software provides, such as managing the delivery of streams to various target bandwidths. Depending on server configuration, bandwidth throughput, and router capacity, a standard HTTP server with a high-end system can broadcast up to 100 or more simultaneous Shockwave or Flash streams. However, with average bandwidth throughput, that same server cannot deliver more than a dozen streams. You can get around this problem by using QuickTime 4 to broadcast your Flash content or by porting your Flash movies into RealFlash and using the RealServer.
Shockwave and Flash are not for everyone. Despite their exceptional interactive controls and authoring environments, there are a few drawbacks and limitations to using either technology:
Creating multimedia. A proprietary authoring environment such as Flash or Shockwave requires web developers to learn an entirely new application as opposed to simply adding a few HTML or SMIL tags. For most developers, this trade-off is well worth it because they can create Flash and Shockwave presentations that look exactly the same on various browsers and platforms, and a standalone authoring application is infinitely more powerful for creating complex interactive presentations.
Replacing or revising content. If developers want to revise content encapsulated within a binary movie using Flash or Shockwave, they must re-export and then upload the entire movie. While it is easier to upload a new audio or graphic file and change a few tags, both Flash and Shockwave support linking to external audio files as a workaround. For an example, check out the SWA CD player application at Macromedia's site (http://www.macromedia.com/shockwave). It can read an external text file to get the song list for a jukebox-style Shockwave movie.
Scalable server solution for managing streams. Macromedia does not provide server-side management tools or dedicated servers for large-scale Flash and Shockwave streaming. Macromedia does support streaming for long-form audio files (audio clips more than a minute long) with RealAudio. Flash animation can be turned into a RealFlash presentation with a synchronized RealAudio clip. Recent versions of Director include a RealAudio Extra that allows you to add RealAudio to Shockwave presentations.
Server-side controls. Shockwave and Flash do not have the server-side controls for random access to different parts of an audio file. If a user connection breaks halfway through an hour-long presentation, there is no way to resume playback at the point where the audio dropped out. The RealAudio Player, by contrast, offers random access to any portion of an audio file by sending a request back to the RealAudio Server.
Live encoding. Shockwave and Flash do not support live encoding and broadcasting. If you want to stream live content, use RealAudio. Flash and Shockwave's inability to broadcast live events is not a problem, however, since interactive content is not usually a live endeavor.
Shockwhat?
When Macromedia launched Shockwave, they labeled the players for all their authoring applications, including Authorware, FreeHand, Director, and Flash, as "Shockwave." By late 1998, Macromedia determined this practice was confusing to consumers and now refers only to the Director player and content exported from Director as Shockwave.
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| 8.9. Summary |  | 9.2. Introduction to Flash |
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