in october 1998, the recording industry association of america filed a lawsuit in the ninth u.s. court of appeals in san francisco claiming the diamond multimedia rio pmp300 player violated the 1992 audio home recording act. the rio pmp300 was significant because it was the second portable consumer mp3 digital audio player released on the market. the three judge panel ruled in favor of diamond, paving the way for the development of the portable digital player market.