In the time it would take to drive to the record store, spend 16.99 dollars on the latest CD, bring it home and pop it in a stereo, a music lover could download the same high-quality recordings over the Internet often for free. Musicians can use MP3 to market their songs directly to consumers, bypassing fickle agents, record companies and distributors by putting audio files on their own web sites, a practice that recently got a rap artist in trouble with his record label, Def-Jam.

If that weren't troubling enough for the recording industry, just in time for Christmas there's Rio, a walkman-like music player that carries about an hour's worth of CD-quality MP3 music on a computer chip. It sells for $ 199, weighs under three ounces and runs for 12 hours on one a battery.

The technology works like this: Users can downloadsongs from the Internet or copy them from CDs and store them on their home computer. An entire album takes about two hours to download, while popping downloaded files onto the rio takes only a few seconds. The Rio lets listeners skip, scan and shuffle through numerous song tracks, all on the go.

The Recording Industry of America Association says artists will be hurt most as bootlegged MP3 files siphon off royalties. The RIAA reported losing 300 million dollars annually prior to the advent of online piracy. Then again, the RIAA said the same thing about cassette tapes, and the music business survived.

``It's a freight train coming down the tracks, and instead of getting on the freight train and going for a nice ride, they're standing in front with their hand out. And it could get ugly,'' said Ken Wirt, a spokesman for Diamond Multimedia Systems, Inc, makers of Rio.

Some MP3 songs proliferating on the Internet are perfectly legal and endorsed by the record labels. There's also a boom in bootlegged tracks,moving that illicit industry from the streets to the Internet.

MP3 stands for Motion Picture Experts Group (MPEG) 1 Layer 3, a method of compressing audio files into digital format that takes up as much as one-tenth the computer memory than previous technologies.

MP3.Com, a popular Internet site that provides MP3 software and music files, legally gives away thousands of full-length MP3 songs from well known artists such as Peter Cetera (formerly lead singer for Chicago), Kansas, The Beach Boys and Willie nelson.

There's a slew of lesser-known artists getting heard, too, such as dance music artist Lucas and funk band 790 Robot Head. Currently, there are an estimated 150,000 songs in MP3 format available on Internet web sites. ``What the Internet does is decentralize the market. On the Internet, it really empowers the artists to sell direct,'' says Michael Robertson, president of MP3.