nd 112 Kbps. One advantage of MP3 is that a sound file can be broken into pieces and each piece remains independently playable. The feature that makes this possible means that MP3 files can be streamed across the net in real time, although network latency can limit the quality of the received signal. The only real disadvantage of MP3 compression is that significant processor power is required to encode and play files. Dedicated MP3 play- ers have recently emerged on the market and are proving to be quite pop- ular, led by Apple's iPod. I received one as a gift from my wife this year; it has a 40 GB hard drive, on which I have now loaded nearly 4,000 songs -and used precisely 8 GB of space. Amazing. MPEG-4 MPEG-4 is a specially designed standard for lower bit rate transmissions such as dial-up video. MPEG-4 is the result of an international effort that involves hundreds of researchers from all over the world. Its devel- opment was finalized in October 1998 and became an International Standard in the first months of 1999. MPEG-4 builds on the proven success of three fields: digital television, interactive graphics applications, and interactive multimedia such as the distribution of HTML-encoded Web pages. MPEG-7 MPEG-7, officially known as the Multimedia Content Description Inter- face, is an evolving standard used to describe multimedia content data that allows some degree of interpretation of the information's actual meaning, which can be accessed by a computer. MPEG-7 does not target any particular application; instead it attempts to standardize the inter- pretation of image elements SO that it can support a broad range of appli- cations. Consider the following scenario. A video editor, attempting to assem- ble a final cut of a video, finds that she needs a specific piece of B-roll (fill- in footage) to serve as a segue and to cover a voice-over during one particular scene in the video. She knows that the footage she needs exists Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringli