A double-sided optical disc introduced in the United States in 2004. A DualDisc features an audio layer similar to a CD (but not following the Red Book CD specifications) on one side and a standard DVD layer on the other. This allows artists to distribute audio-only versions of their work in both 16-bit/44.1kHz CD and high-resolution (24-bit/96 or 192kHz) DVD-A stereo file formats, as well as include surround versions and video content.
Technically speaking, DualDisc is not a “format” in the sense of Red Book CDs or DVD-Audio. The media is an attempt by several industry giants (EMI Music, Universal Music Group, Sony/BMG Music Entertainment, Warner Music Group, and 5.1 Entertainment Group) to deliver albums that can be played on any optical disc player, whether CD or DVD, in a single package. One side is the “standard” full-length CD audio album. The other side offers DVD content. This may include enhanced album audio, 5.1 surround sound, music videos, artist interviews, behind-the-scenes footage, documentary films, photo galleries, lyrics, computer-ready digital song files, and Web links – whatever the artist chooses to include.
Although the recording industry is enthusiastic about this delivery system, the future of DualDisc is far from clear. As of 2005 it’s still sitting under a cloud of patent-infringement lawsuits from the European company DVD Plus, which claims to have originally developed the technology. In addition, forthcoming optical technology such as Blu-Ray and HD-DVD, with massive file storage capacity, might replace both CD and current DVD technology.