"An MPEG-1 Audio Layer 3 (commonly known as MP3) is the most popular digital audio compression algorithm in use on the Internet, and the compression it provides makes an audio file 'smaller' by a factor of 12 to one without significantly reducing sound quality. MP3's popularity is due in part to the fact that it is a standard, non-proprietary compression algorithm freely available for use by anyone, unlike various proprietary (and copyright-secure) competitor algorithms."
"In 1987, the Moving Picture Experts Group set a standard file format for the storage of audio recordings in a digital format called MPEG-3, abbreviated as 'MP3.' Digital MP3 files are created through a process colloquially called 'ripping.' Ripping software allows a computer owner to copy an audio compact disk ("audio CD") directly onto a computer’s hard drive by compressing the audio information on the CD into the MP3 format. The MP3’s compressed format allows for rapid transmission of digital audio files from one computer to another by electronic mail or any other file transfer protocol."
Importance of MP3 technology
Prior to the introduction of digital audio recording, individuals wanting to copy a sound recording were limited to analog technology. Successive copying by analog techniques resulted in increased degradation of sound quality. Hence, copyright infringement by unauthorized duplication of cassettes and CDs was frustrated by the inability of a copier to replicate music with high quality sound.
The introduction of digital audio recording to consumer electronics during the 1980s facilitate high quality mass copying. Music pirates were able to use digital technology to make and distribute near perfect but infringing copies of commercially prepared recordings.
Prior to the advent of MP3 technology, however, the Internet was not a feasible vehicle for music distribution because the average music computer file was too big. MP3 uses perceptual audio coding and psychoacoustic compression to remove the redundant and irrelevant parts of a sound signal.
MP3 files can be encoded at different “bit rates” — the lower the bit rate, the smaller the file and the poorer the sound quality. An MP3 file encoded at 64 kbps is roughly equivalent to FM radio, which is of a noticeably lower fidelity than audio CDs.
- Recording Indsutry Ass'n of America v. Diamond Multimedia Sys., Inc., 180 F.3d 1072, 1074 (1999)(full-text).
- A&M Records, Inc. v. Napster, Inc., 239 F.2d 1004, 1011 (9th Cir. 2001)(full-text).
- Jim Esch, "Slicing and Dicing MP3 Bit Rates" (full-text).