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AmigaOS 4.0 - About OS4 - Commands

Purpose: To play audio CDs.
Format: PLAYCD [<dos device>] [<device>] [UNIT <unit>] [SKIP <skip>] [PT | PEEKTIME <peek time>] [PUBSCREEN <public screen name>] [BT | BUFMEMTYPE <memtype>] [USECDDB] [URL <url>] [PROXY <proxy>] [USER <user>] [CACHEDIR <cache>]
Path: SYS:Tools/PlayCD
PLAYCD acts as a user interface for the audio CD playback functionality offered by a CD-ROM drive. The CD-ROM drive in question must comply to the SCSI-2 standard and thus support at least a subset of the audio control commands defined for CD-ROM drives.

When the program is launched, it will attempt to configure itself. This involves figuring out which device driver and which device unit to use for audio playback. This information is usually stored in the program's icon, but it can also provided on the command line. The names of the command line options and the tool types are the same. The following options are supported:

The DOSDEV <dos device> argument (the DOSDEV keyword is optional) can be used if there already is a filing system mounted on the CD-ROM drive to use for audio playback. The easiest way to tell PlayCD which device it should use is to provide that filing system's name. PlayCD will try to figure out which device and unit that filing system is bound to and use the resulting information. There is no default for this option, but in most instances it can simply be set to "CD0".

The DEVICE <device> argument (the DEVICE keyword is optional) can be used to provide the name of the device driver the CD-ROM drive to use for playback responds to. The default for this option is "scsi.device".

The UNIT <unit> argument works in conjunction with the DEVICE argument. Both the device name and the unit number specified define the interface PLAYCD should use to address the CD-ROM drive. The default for this option is "2".

The PLAYCD user interface has a slider which displays (and controls) the position within the current track thst is playing. Attached to this slider are two buttons which perform "fast forward" and fast rewind" functionality. Pressing either of these buttons will cause playback to skip a few seconds. The SKIP <skip> argument is used to configure the number of seconds to skip. The default for this option is "1 second", i.e. clicking once on the buttons will skip one second in the respective direction, while holding the button down will repeat this approximately 10 times per second.

PLAYCD queries the CD-ROM drive at regular intervals to find out whether the CD was changed or how far playback has progressed. The length of these intervals is configured with the PT or PEEKTIME <peek time> argument. The peek time is specified in microseconds, i.e. one millionth part of a second. The default for this option is "200000", i.e. one fifth of a second.

The PUBSCREEN lt;public screen name> argument can be used to specify a public screen name where PLAYCD will open. There is no default for this option. Default behaviour for PlayCD is to open its display on the default public screen which in most cases will be the Workbench screen.

PLAYCD depends upon the controller hardware the CD-ROM drive is attached to in order for it to deliver its commands properly. This may sometimes require that the command data structures are passed in a particular type of memory which the controller hardware has easy access to. In most cases you will not need to change this option, but if the CD-ROM drive is correctly configured, does support the SCSI-2 command set and still does not react to PlayCD`s commands, then it might be necessary to specify a different buffer memory type. The BT or BUFMEMTYPE <memtype> argument can be used to specify the required memory type; 0,1=Any, 2,3=Chip, 4,5=Fast RAM - hardly relevant for PPC based machines. The default for this option is "0" which specifies no particular type of memory to use for interacting with the controller hardware, while the value specified for this option in the supplied icon is "1".

The USECDDB option causes PLAYCD to attempt to extract the CD details from an online CDDB database.

The URL <url> argument is used in conjunction with the USECDDB option, and specifies the URL for the CDDB database. The default is "freedb.org:80/~cddb/cddb.cgi". We have found that the default doesn't always work, and results in an error messsage "Could not process HTTP header (object is not of required type)", but 'freedb.freedb.org/~cddb/cddb/cgi" seems to resolve this issue.

The PROXY <proxy> argument is used in conjunction with the USECDDB option, and specifies a proxy address if one is required. There is no default.

The USER <user> argument is used in conjunction with the USECDDB option, and supplies the user name to log on if one is required. There is no default.

The CACHEDIR <cache> argument specifies the location of the local cache directory where CDDB information can be stored. The default is SYS:Tools/CDDB-Cache.

Instructions for using PlayCD are here.

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Disclaimer: Amiga Auckland have prepared the above information for the use of its members based on our experiences and as such is subject to revision at any time. Amiga Auckland cannot guarantee any of the information and cannot be held accountable for any issues that may result from using it.

Copyright 2006 Amiga Auckland Inc. All rights reserved.
Revised: February 9, 2006.