Created 10 Nov 97
CD Extra is a relatively new CD format promoted by Philips and Sony and backed by major computer suppliers including Microsoft and Apple. It provides a way of adding CD-ROM and computer data to a music CD without stopping the CD working as a normal audio CD in an ordinary HiFi CD Player. It also allows information about the music, such as the names of the performer and composer, track titles and even an image of the disc's jacket to be stored on the CD. This additional information can be displayed by a new generation of HiFi and home entertainment products.
A growing number of CDs are now produced as CD Extras. BBC Music Magazine has adopted the format on its December 1997 CD, a new recording of Handel's Messiah, to include an interactive listening guide and background articles on the music for readers to try on their Windows PC computers. It seems set to grow in popularity as more and more people have multimedia computers available and as many music CDs have enough space on them to provide a reasonable CD Extra section.
CD Extra is based on a multi-session CD with two sessions. The first contains the audio tracks and the second has the computer data in it (this CD-ROM section also contains the additional information such as track titles and images for CD-Extra aware HiFi players).
An ordinary HiFi player is a single session device and simply does not see the computer data. Modern computers have multi-session CD-ROM drives that should, by default, see the last (second) session on the disc, making the disc appear to be a CD-ROM. When the PC asks to play audio from the CD, it is automatically read from the first session.
The major issue for CD Extra is that while it works on all HiFis, it doesn't work on all computers. Firstly, it requires a multi-session type CD-ROM drive or else only the music tracks will be visible to the computer. Almost all modern CD-ROM drives are multi-session but many older PCs have either single-session drives or drives which need a hardware upgrade (changing ROM chips) before they will work properly.
Secondly, the PC's driver software must recognise and handle the CD Extra format. This is fortunately not a problem on the majority of Windows 95 PCs as Windows 95 is designed to provide CD Extra support. It does cause difficulties for users with older PCs running Windows 3.1 or 3.11 (Windows for Workgroups) where far fewer machines were supplied with suitable drivers or with PCs that have been updated to run Windows 95. Many of these systems predate CD Extra so it's not reasonable to expect it to work and users may find that manufacturers never went back and updated drivers now that their product line has moved onto more modern systems.
BBC Music Magazine has chosen to adopt CD Extra for the same reason that many other publishers are now switching to it; it looks to be the best method at present of combining computer data and music on the same CD and to be a widespread standard for the future.
More specifically, while it is sadly recognised that many readers won't be able to enjoy the interactive listening guide on their existing PCs, the magazine did not want to inconvenience the majority of its readers who just enjoy its CDs as music CDs. Other methods of combining computer data with music may work on more computers but will inconvenience those playing the disc on a HiFi.
Early indications from the December 1997 CD are that this has been the right choice...
©Copyright 1997 Strange Software Limited. All rights reserved.