On computers, movement is in the eye of the beholder. Nothing on our screens ever really moves--it's just dots changing color. But our brains, poorly trained by a lifetime of exposure to reality, are easily deceived. When a block of color turns off, and an identical one nearby immediately turns on, it looks like motion. There are lots of ways to execute this simple trick, and several technologies that threaten to make Web pages dizzyingly active. All these methods have advantages and disadvantages, which is why none of them has yet become the Web standard.
The most familiar of these technologies is, or should be, video. After all, we all live with video, which shows a rapid sequence of pictures, often accompanied by a synchronized soundtrack. The more pictures ("frames") per second, the more realistic the depiction seems. But video has two problems: It's big, and it's slow. Storing all those individual pictures in digital form takes a lot of disk space, and the audio portion isn't tiny either. As for speed, until recently, computers weren't capable of displaying pictures on the screen rapidly enough to simulate motion. Even today the best results require special hardware. Computer video has come a long way--but it has a long way to go. Apple's QuickTime and Microsoft's AVI (Audio Video Interleaved) are the competing giants of computer video technology, and SLATE uses both. Here, for example, are the QuickTime and AVI versions of a film clip that ran with our recent review of a Jackie Chan film.
For modem users, video poses a special challenge--you can't transmit a reasonably sized video in anything like a reasonable amount of time. A typical 30-second video takes around 16 minutes to transmit at 14.4K. Video can be compressed, which makes it "smaller" (meaning, in computerese, that it requires less digital information, not that the picture itself is necessarily smaller) at the price of reduced quality. Compress video enough, and you can stream it. Streaming essentially means sending one second of video every second. When the Internet can deliver a video clip in no more time than it takes to watch it, it will have achieved what ordinary television did half a century ago. And we are getting there. Vivo and other companies are competing to develop this technology, but so far, quality still remains low. In the end, good results are likely to come more from faster modems than from better compression software, but I hope to be proven wrong about that. WebTV, which designs boxes that allow your television to access the Internet, recently announced what it termed a breakthrough on this front.
Far simpler than video--and more common on the Web--is the animated GIF. GIF (Graphics Interchange Format) is a technology that was developed by CompuServe to transfer still images. The animated GIF basically packages several GIF images together. Your computer then plays them like a flip book. Many Web advertisements are animated GIFs, for better or for worse. The advantage of these is that they are easy to create, and no special software is required to view them. For simple animations, they can also be quite small (the animated GIF below is 1K of data). But even mildly complex animations are still mostly out of the question, for the same reason that they didn't release Gone With the Wind in a flip book.
Here are three separate GIFs and the animated GIF that is created by combining them:
Let's look back in time for a moment. The past masters of animation created complex, full-length cartoons, using some tricks. Instead of painting each frame, they created layers of transparent "cels." The background (for instance, the sky) didn't move at all. Several layers of middle ground (for instance, waves and a boat) moved independently. And in the foreground, characters (for instance, pirates) interacted, independent of what lay beneath them. This was truly inspired, because it minimized the work involved in creating each frame. It turns out that this model works very well with computers, too. For years, video games have relied on moving "sprites" around on multiple layers on the screen. Macromedia's Director embodies this technique. An artist defines several images and then writes a "script" saying what the images should do. These are packaged together into a "movie," which your computer replays to you by moving the images around according to the script. This is much more efficient than a video or an animated GIF, because a movie consisting of thousands of frames might involve only several images, and is thus much smaller. Macromedia makes free Internet software called Shockwave that allows your computer to play Director movies right on a Web page. Today's Web-site developers face a difficult quandary. A site that is to stand out from others requires higher production values and, often, the addition of motion to grab the eye. But video is too large, and animated GIFs are not very flexible. Director movies are flexible, but can still take too long to load for the short attention spans of Web surfers, for whom even 40 seconds can be too long to have to wait. A different idea is needed. Think about the incidental animations you see on television, such as show credits, introductions to local news, and sports statistics. Most of these are textual--words spinning around, zooming in and out, and changing color and size. Macromedia recently bought a technology called FutureSplash (renamed Flash) that specializes in just this. Flash movies are tiny--they're really just descriptions like, "Rotate a giant red 'Bill is a so-so columnist' in the center of the screen." By keeping things simple, Flash succeeds where its stepbrother, Director, sometimes stumbles. Director and Flash both require special (free) software on the viewer's machine. Both exist only for the "big two" browsers-- Microsoft Internet Explorer 3.0 and Netscape Navigator 3.0--on the "big two" operating systems, Windows and Macintosh. Take a look at this simple Flash movie. It's only 6K in size, so it should have loaded by the time you read this. If you aren't seeing the animation, you can download the software here.
Java is a programming language from Sun that is meant to solve some of these problems. Java is part of most modern browsers on most operating systems, and any Java program is supposed to run the same on all of them. In the right hands, Java can be used to create animations more complex than Flash and Director movies. Eventually, Java probably will save the universe; but currently, Java programs load and run too slowly. In fact, many sites have used some Java, only to pull it because of complaints. At this writing, however, the folk at CNN still use it for their breaking news.
In a more specialized vein, VRML (Virtual Reality Modeling Language) is a technology that allows you to "walk through" 3-D images. This technology is very useful for designing houses, less useful for illustrating Web sites, but as it evolves we'll probably see more of it. A 3-D visualization of a search site is like a walk through a library, with stacks of "books" representing collections of related sites. Your family's home page might be a model of your home, where you walk into each person's room to find out more about him or her. To demonstrate this technology, Microsoft hosts a VRML walk-through of its campus.
Many letters that SLATE receives thank us for keeping it simple--and in fact, as a rule, we have forsworn glitz in favor of content. But as technologies improve, we are not beyond adding attractive graphics to enhance the reading experience. Animated budget battles? Probably not. But as the Web audience broadens, even SLATE might not be able to remain inanimate.