Audio for the Worldwide Web

There's a revolution under way in the audio world. Personal computers are now powerful enough to be viable professional audio workstations. Musicians and recording enthusiasts are like kids in an ear-candy store, as audio recording gets better, easier and cheaper at an amazing tempo.

Meanwhile, there's another little revolution going on, called the Worldwide Web. Web pages are by no means limited to text and graphics. All major browsers can handle a variety of audio (and video) formats with ease, and including audio on a Web site is theoretically no more complicated than including graphics. Web audio is booming in certain areas such as Internet radio stations and online music distribution, but few mainstream Web sites include sound. Why is the Web still mainly a silent world? The main reason is simply bandwidth.

Digital audio files are large. CD-standard audio (44.1 kHz, 16-bit stereo) hogs up about 10 megabytes per minute. Even with a fast modem, forget it. It takes far longer to download an audio clip than it does to play the darn thing back. In the sweet bye-and-bye, when we all have bandwidth to burn, we'll look back on these days and laugh as we download whole albums and movies in a femtosecond. For now, however, if Web audio is to happen at all, every trick in the book must be used to slim it down to a manageable size, or otherwise get around the bandwidth bottleneck.

Fortunately, there are all kinds of tricks in the book, and some of them work pretty well. The obvious first step is to reduce the file size. Of course, this reduces the sound quality as well, but the mother of invention tends to leave some eggshells around when she makes an omelet (or something like that). 22.05 kHz, 8-bit mono is a fairly standard format for lower-fidelity applications like CD-ROMs, and is usually considered adequate quality for speech, if barely tolerable for music. Files in this format are one-eighth the size of CD-standard audio (44.1 kHz, 16-bit stereo).

By the way, ordinary file-compression schemes like WinZip don't work worth a darn for audio. To compress audio or video files, you need a special type of compression scheme called a "codec" (so called because it codes and decodes data). There are many codecs out there, but the only ones that are really popular for audio are the various versions of MPEG, including the current rage, MP3 (more on this below).

For short clips like sound effects, dog barks (http://SassyDog.com) and so forth, the best bet is usually simply to include a wave file in the page (in a low-quality format to minimize download time). As we'll see below, it's very easy to set up a short audio clip to play automatically when a Web page is opened, or to play in response to various kinds of events. For music, however, simply embedding a sound file like this will never do. A musical piece of any length will take forever to download, and the quality doesn't really make it worth waiting for. If you want to add a "background track" to a Web site, there are two more appropriate ways to do it: the old standby MIDI, or the more cutting-edge streaming audio.

Contents:

• MIDI for the Masses
• Streaming Audio
• Including Sound in a Web Page
• The Next Wave
• For Further Reading:

MIDI for the Masses