Enhanced CD, also known as CD Extra and CD Plus, is a certification mark

Certification mark

A certification mark on a commercial product indicates five things:* The existence of a legal follow-up or product certification agreement between the manufacturer of a product and an organization with national accreditation for both testing and certification,* Legal evidence that the product was...

 of the Recording Industry Association of America

Recording Industry Association of America

The Recording Industry Association of America is a trade organization that represents the recording industry distributors in the United States...

 for various technologies that combine audio and computer data for use in both Compact Disc

Compact Disc

The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...

 and CD-ROM

CD-ROM

A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....

  players.

The primary data formats for enhanced CDs are mixed mode

Mixed Mode CD

A Mixed Mode CD is a Compact Disc in which two different data types are combined. Typically the first track is a data track while the rest are audio tracks...

 (Yellow Book/Red Book

Red Book (audio CD standard)

Red Book is the standard for audio CDs . It is named after one of the Rainbow Books, a series of books that contain the technical specifications for all CD and CD-ROM formats.The first edition of the Red Book was released in 1980 by Philips and Sony; it was adopted by the Digital Audio Disc...

), CD-i

CD-i

CD-i, or Compact Disc Interactive, is the name of an interactive multimedia CD player developed and marketed by Royal Philips Electronics N.V. CD-i also refers to the multimedia Compact Disc standard used by the CD-i console, also known as Green Book, which was developed by Philips and Sony...

, hidden track, and multisession (Blue Book

Blue Book specification

The Blue Book or Enhanced Music CD specification describes the Enhanced Music CD format. The first session of an Enhanced Music CD contains audio information according to the Red Book...

).

The technology was popular in the late 1990s with the increase of computer usage. Music CDs often included music videos, wallpapers, and other various content.
However, more recently, acts wishing to include enhanced content often include a DVD instead, with the advantage of it playing in both a computer's DVD-ROM drive and in a standard DVD player. Iron Maiden

Iron Maiden

Iron Maiden are an English heavy metal band from Leyton in east London, formed in 1975 by bassist and primary songwriter Steve Harris. Since their inception, the band's discography has grown to include a total of thirty-six albums: fifteen studio albums; eleven live albums; four EPs; and six...

 was one of the first bands to use Enhanced CDs in 1998 when the group released remastered albums of its back catalog.

Problems

Sometimes computer CD-ripping programs (particularly cdparanoia

Cdparanoia

cdparanoia is a compact disc ripper for *nix and BeOS, developed by Xiph.org. It is designed to be a minimalistic, high-quality CD ripper that would be able to compensate for and adjust to poor hardware to produce a flawless rip....

) have problems ripping some enhanced CDs, especially those that have the data in a separate session after the audio section. These CDs have the data 11,400 sectors (2m32s) after the audio, but some CD rippers may try to rip this blank section with the last track; the end result is that the ripper stalls during the last track or simply reports errors.

External links

• Enhanced CD Fact Book (PDF file) 09/18/2011 the file isn't coming up