56 PA R T I Understanding Digital Music data encoded throughout the course of a recording, using a lower bitrate when there's less complex audio content and a higher bitrate with the content is more complex. The result is, theoretically at least, a better sounding record- ing that takes up slightly more space than one with constant bitrate encoding, but still less than with a comparable lossless format. When choosing a file format, then, you need to consider both compression and bitrate. For better sounding playback, go with a higher bitrate; to con- serve on storage space, choose a lower bitrate. Comparing the Major Digital Music Ecosystems Lossy, lossless, or uncompressed files, at a lower or higher or variable bitrate. That's a lot of factors to consider, but there's one more that bears attention-- the ecosystem or "family environment" built around the most popular for- mats. I'm talking about the fact that certain formats work best with certain music player programs and hardware devices; if you're already wedded to a given ecosystem (based on the equipment and software you use), your choice in terms of audio format may be limited. 4 Let us look, then, at the three major format ecosystems for digital audio today--MP3, Apple, and Windows. Chances are you're invested in at least one of these. The MP3 Ecosystem Of all the available digital audio file formats, the one that has enjoyed almost universal popularity is the MP3 format. That's because MP3 was the first widely accepted format that combined good quality sound with reasonably small files. As you know, MP3 is a digital audio file format that uses lossy compression. Developed (and patented) by Thomson Multimedia and the Fraunhofer Institute, the MP3 digital audio format is an extension of Motion Picture Experts Group (MPEG) technology. (The MP3 file extension is short for MPEG-1 Audio Layer III.) MP3 and other MPEG formats store music digitally, and in the process compress the original data to take up less space than it did origi- nally. MP3's data compression reduces digital sound files by about a 12:1 ratio. Naturally, the MP3 format allows for sampling at various bitrates. Table 4.2 details some of the more popular bitrates for MP3 files, and describes the sound quality of each.