A US Court of Appeals panel has ruled that the MP3 audio compression format space-shifts digital music files in the same way a video recorder time-shifts television shows. That ruling implies that copying legitimately obtained files with MP3 technology should be considered fair use under copyright law. The landmark decision is a blow to the Recording Industry Association of America (RIAA) in its lawsuit against Diamond Multimedia Systems Inc. Ironically, by pressing its case against Diamond’s Rio portable MP3 player, RIAA may have helped legitimate the widespread use of MP3.

RIAA sued Diamond on the grounds that the Rio violated the Audio Home Recording Act of 1992. But the court ruled that the Act does not apply to the Rio, since it is not a digital audio recording device but a computer peripheral. Judge Diarmuid O’Scannlain, who wrote the three-judge panel’s unanimous decision, noted that: The Rio merely makes copies in order to render portable, or ‘space-shift’, those files that already reside on a user’s hard drive. RIAA is reportedly disappointed with the decision, but determined to press ahead with the Secure Digital Music Initiative, its own copyright-protected alternative to MP3.