TITLE
    Enhanced CDs: Audio Intermittently Stops Playing
Article ID:
Created:
Modified: 		19112
12/21/95
10/2/98
TOPIC

    When I play audio tracks on enhanced CD (CD Plus or CD+) format CD-ROM discs, the music will stop playing when I access other applications from the Finder, or won't play at all. This does not happen with audio-only CDs. What is the difference between these CD formats, and what is causing the problem?

DISCUSSION

    There are several things that you must consider regarding this issue.

    Enhanced CDs are essentially split into two partitions, a data part and an audio part. The data part usually mounts on the desktop and gives the user access to multimedia features of the CD including the audio, which is not accessed from the audio partition; it's duplicated on the data side. The audio part contains audio CD tracks pretty much like any other audio CD. However, even though there are two parts to the CD, there is only one laser accessing the CD and that laser can only be in one place at a time. If the laser is reading audio data from the audio part of the CD (using AppleCD Audio Player for example) and there is a demand for information from the data part of the CD, the laser must move and the audio will stop playing.

    This occurs with AppleCD Audio Player, AppleCD Player and the CD Control Strip, on all Macintosh models, when using enhanced CDs. Note that these symptoms can also occur with standard audio CD-ROM discs that are not multisession enhanced CDs if the Hong Kong Virus, (also known as the Autostart Worm) has infected the computer's drives.

    A workaround for this may be to use FWB's CD-ROM Toolkit. Use version 2.0.6 or greater for SCSI drives and 2.5.1 or greater for ATAPI drives. You can also minimize the chances of the problem occurring by increasing the disk cache in the Memory control panel. Note that any memory allocated to the disk cache will not be available to run programs.

    Yet another tip is to launch any applications you plan on using before starting the audio on the CD. This can help because many applications scan the catalog files of all mounted volumes when they are launched.

    CD-ROM Drives
    There is a known problem with early versions of quad-speed (4X) drives used by Apple that did not allow the drive to read multisession data CD-ROM discs. If you continue to have problems reading multisession CD-ROM discs after checking the issues below, see an Authorized Apple Service Provider for further troubleshooting.

    CD-ROM Setup Software
    You should install the latest version of CD-ROM Setup (version 5.3.2 or greater) for complete compatibility with multisession data CD-ROM discs.

    Enhanced CD Titles Created With Apple Media Tool 1.0-1.2
    Many titles created with Apple Media Tool version 1.2 and earlier have a problem known as the AMK Spinning Cursor Bug. This is fixed with the software of the same name posted in Apple SW Updates area of online services. The latest version of Apple Media Tool is 2.1.1.

    Interactive Music Formats
    The last thing to know is that there are several formats of interactive music discs on the market.
    • Yellow Book CD-ROM only.
    • Yellow Book CD-ROM Hybrid disks with data in track 1 that may damage audio players, or users ears.
    • Hybrid discs with CD-ROM and Red Book audio tracks, known as a track 0 solution.
    • Hybrid discs with Macintosh and Windows partitions - ISO-9660 compatible.
    • Multisession CD-ROMs with separate CD-ROM and Red Book audio volumes.
    • Blue Book standard discs by whatever name it is called. These CD-ROM discs will be stamped multisession discs with Red Book audio tracks.
    These articles can help you locate the software update mentioned here:

    " Where To Find Apple Software Updates " - Lists online services for free Apple software updates.

    " Obtaining Apple Product Support in the USA " - Lists 800 numbers and online services for software updates, Apple support information, and a subset of the Apple Tech Info Library.


    This article was published in the 6 June 1997 "Information Alley".

Document Information
Product Area: Peripherals
Category: CD-ROM
Sub Category: General Topics

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