xmcd(1) CD digital audio player utility for X11/Motif


xmcd [toolkitoption ...] [-dev device] [-instcmap] [-remote] [-rmthost hostname] [-help] [-debug] [-c device] [-X] [-o] [command [arg ...]]


Xmcd is a program that allows the use of the CD-ROM, CD-R or CD-RW drive as a full-featured stereo compact-disc player for the X window system. See cda(1) for the command-line CD player. xmcd and cda uses the same configuration and support files.

Most of the features found on "real" CD players are available in xmcd, such as shuffle and repeat, track programming functions, a numeric keypad and track warp slider for direct track access. Additional functions include sample play, A to B segment play, volume control, balance control, etc. Several automation options are also available on CD load, eject, play completion and program exit. A Channel Routing feature allow you to select from several stereo or mono routing options. The volume control slider taper characteristics can also be altered.

Multi-disc changers are also supported. There are buttons to switch to the next or previous disc in the changer, as well as a way to specify a specific disc via the keypad. You can select to play only a single disc or auto-play all discs in normal or reverse order.

A CD database feature allows the CD artist/title and track titles, and other associated general purpose text to be maintained and loaded as the program is started or when a CD is inserted. The CD database contents can be on your local system or queried from a remote CD database server host. There are a number of worldwide Internet public CD database servers in operation, serving in both CDDBP (CD database protocol) and HTTP (Hyper-text transport protocol). Xmcd supports both of these protocols.

Xmcd provides the ability to drive a web browser and search for web sites related to the currently playing CD artist or track. You may also drive the web browser via xmcd to access online music reviews and go to the official xmcd and CDDB web sites. Moreover, the browser integration gives users the ability to manage local discography information pertaining to his or her CD collection.

Full feature-specific pop-up help is available for all controls, indicators, text input fields, and lists.

On systems with more than one CD-ROM or CD-R drive, multiple invocations of xmcd can be used to operate each drive independently.

Xmcd is designed to be easy to use, as the main window is purposely made to resemble a real CD player front panel. All other pop-up windows are also designed to be as intuitive as possible. Moreover, while the use of a mouse is natural with xmcd, all functionality can also be operated via the keyboard. This is in conformance to the guidelines published in the OSF/Motif Style Guide from the Open Software Foundation.

Many functions on a running xmcd session can be "remote controlled" from the command line via the -remote option. See the OPTIONS section below.

The internal architecture of xmcd is designed to be easily portable to many UNIX operating system variants, and adaptable to the myriad of CD-ROM drives available.


All standard Xt Intrinsics toolkit options are supported (such as -display, -geometry. -iconic, etc.). In addition, xmcd supports the following options:
-dev device

Specifies the path name to the raw CD-ROM device. If this option is not used, the default device to be used is the first drive set up with the xmcd configuration program (See below).
Causes command line usage information to be displayed on stderr.
Causes verbose debugging diagnostics to be displayed on stderr.
Causes xmcd to install its own colormap. This may be desirable if xmcd is to be used at the same time as other color-intensive applications, which would otherwise cause xmcd to be unable to allocate all its needed colors. Note that when running on an X display that does not support many concurrent colormaps, this may cause other windows to change colors when xmcd has the input focus.
Causes a command to be sent to another running xmcd process. The command and appropriate arguments are specified at the invoking shell (or shell script) as command-line arguments, After the command is delivered, the "sender" xmcd process exits, and the "receiver" process responds by executing the command. In effect, the sender becomes a remote control for a running xmcd session. See "COMMANDS" below for a list of supported commands.

The sender xmcd process can be invoked on the same host or on a different host than the receiver xmcd process. By default, the sender will attempt to locate an xmcd process running on the same X display (determined by the DISPLAY environment variable or the -display option), and controlling the same default CD-ROM device. You may specify the device via the -dev option to override the default. Use of the -dev and -rmthost options on the sender's command line can resolve ambiguities when there are multiple xmcd clients displaying on the same X server.

-rmthost hostname
This may be used with the -remote option to specify the host on which the receiver xmcd client must be running.
-c device (Solaris only)
Same as the -dev option.
-X (Solaris only)
Causes the exitOnEject parameter to be set to True.
-o (Solaris only)
This option has no effect.

The -c, -X and -o options are provided only on the Solaris platform for compatibility with the action_workman.so auto-startup program, running under the Solaris Volume Manager (vold). See the README file in the xmcd distribution about configuring xmcd for the Solaris Volume Manager.


Xmcd has many adjustable X resources to customize its look and feel, as well as its behavior. Notably, the colors of virtually every feature on xmcd's windows can be changed, as well as the text fonts. All text labels can also be changed (for example, to another language).

There are too many resources to list here, but the resource names and their defaults (plus descriptive comments) can be found in the XMCDLIB/app-defaults/XMcd file (where XMCDLIB is typically /usr/lib/X11/xmcd). It is not recommended that you change values in the XMCDLIB/app-defaults/XMcd file, unless you want the changes to be forced upon all users of xmcd on the system. Instead, make a copy of this file, change the copy as you see fit, then place it in your home directory. Your custom resource settings will then override the defaults when xmcd is subsequently started. Alternatively, you may also place specific resources you wish to override in the .Xdefaults file in your home directory.


You may specify a command as an xmcd command line argument, to make xmcd execute the command after initial startup. For example, the following command starts xmcd and then begins playing at track 4:

xmcd play 4 &

If the -remote option is used, then the command is sent to another running xmcd process for execution (See "OPTIONS" above).

The supported commands are:

Stop playback.
play [track# | min:sec | track#:min:sec]
Start playback. You may also specify the starting track number, and/or the starting minute and second offset.
Pause the playback. You may resume the playback by using either the pause command again, or the play command.
Start sample playback. This will play each track for 10 seconds.
disc <load | eject | prev | next | disc#>
Perform a disc operation: Load or eject the CD, or change to another disc on a multi-disc changer.
track <prev | next | track#>
Perform a track operation: Change to the previous or next track, or a specified track number.
index <prev | next>
Perform an index operation: Change to the previous or next index.
lock <on | off>
Enable or disable the caddy (or disc tray) lock. When enabled, pressing the eject button on the drive will not eject the CD.
shuffle <on | off>
Enable or disable shuffle (random play) mode.
repeat <on | off>
Enable or disable repeat mode.
program <clear | track# ...>
Set or clear a track program sequence. Track numbers may be space or comma-separated.
volume <value# | linear | square | invsqr>
Volume control operation. You can specify a numeric value to set the volume level (The range is 0 to 100), or change the volume control's taper characteristic: linear, square, or inverse-square.
balance value#
Balance control. The value should be between 0 and 100. 50 is center, 0 is full-left, and 100 is full-right.
route <stereo | reverse | mono-l | mono-r | mono | value#>
Channel routing control. Use one of the appropriate keywords, or a value as follows:

0       Normal stereo
1       Reverse stereo
2       Mono-L
3       Mono-R
4       Mono-L+R
time <elapse | e-disc | r-trac | r-disc>
Change the time display mode. Select from elapsed track time, elapsed disc time, remaining track time, or remaining disc time.
on-load <autolock | noautolock | none | spindown | autoplay>
Enable or disable options when a CD is loaded. The autolock option causes the caddy or disc tray to be automatically locked, The spindown option will cause the CD to stop after loading to conserve the laser and motor. The autoplay option will cause the CD to automatically start playing after loading. The none, spindown and autoplay options are mutually-exclusive.
on-exit <none | autostop | autoeject>
Enable or disable options when xmcd exits. The autostop option will cause xmcd to stop playback, and the autoeject option will cause xmcd to eject the CD. Use none to cancel these options.
on-done <autoeject | noautoeject | autoexit | noautoexit>
Enable or disable options when xmcd is done with playback. The autoeject option causes xmcd to eject the CD. The autoexit option will cause xmcd to exit.
on-eject <autoexit | noautoexit>
Enable or disable options when xmcd ejects a CD. The autoexit option will cause xmcd to exit after ejecting the CD.
changer <multiplay | nomultiplay | reverse | noreverse>
Enable or disable multi-disc changer options. The multiplay option specifies that xmcd plays all discs in sequence. The nomultiplay option will cause xmcd to stop after the current disc is done. The reverse option implies multiplay, except that the disc order is reversed.
window <modechg | iconify | deiconify | raise | lower>
Xmcd window control. The modechg command causes the xmcd main window to toggle between the normal mode and basic mode. In normal mode, all controls and indicators are available. In basic mode, xmcd shrinks to a smaller size and only basic controls are shown. The iconify, deiconify, raise and lower commands cause the xmcd window to change as specified.
Causes xmcd to exit.
debug <on | off>
Enable or disable debug mode. When debug mode is enabled, xmcd generates verbose debugging diagnostics to be displayed on stderr.

Some of these commands, when used in start-up mode, do not perform a meaningful function. For example, the "track prev" command is not useful just after xmcd startup. It is more appropriate to use this command in the remote control mode.


The X resources described in the previous section affect the general appearance and behavior of xmcd. There are two additional configuration files which are used to adapt xmcd to your site requirements. The first of these contain common parameters, and the second contain configurable parameters that must vary on a per-drive basis. For example, in some cases xmcd must operate the drive differently depending upon the brand and model of the drive. Thus, there must be a separate configuration file for these parameters per-device. The common parameters file is XMCDLIB/config/common.cfg and the device-specific parameters file is XMCDLIB/config/DEVICE (where XMCDLIB is typically /usr/lib/X11/xmcd and DEVICE is the base name of the raw device special file for the CD-ROM drive ; e.g., /usr/lib/X11/xmcd/config/rcd0). A configuration program XMCDLIB/config/config.sh is provided to make maintaining these configuration file easy (Note: on SCO systems the configuration program can also be invoked as "mkdev xmcd").

You should always use the configuration program to set the configuration parameters when installing xmcd for the first time, or when the CD-ROM hardware configuration has changed. If this is not done then xmcd will probably not operate correctly with your CD-ROM drive.

WARNING: If xmcd is not correctly configured, you may cause xmcd to deliver commands that are not supported by your CD-ROM drive. Under some environments this may lead to system hang or crash.

You can override some of the device-specific configuration parameters by adding your own configuration files. Xmcd will also look in the HOME/.xmcdcfg/common.cfg and HOME/.xmcdcfg/DEVICE files for common and device-specific parameters (where HOME is your home directory and DEVICE is as specified above). Parameters found in this file will override the system defaults (except those parameters that cannot be overridden; see the comments in the XMCDLIB/config/device.cfg for details).


The basic functions of xmcd are designed to operate the same way as on a real stereo CD player. The pictorial symbols used on the main window buttons are intended to illustrate the function in a non-language-specific manner. If enabled, a small "tooltip" will appear after a short delay, when you position the mouse cursor over any xmcd main window feature. The tooltip contains textual description of the feature.

The CD database and track programming functions are operated via the CD Database/Track Program Editor pop-up subwindow. You activate the subwindow by clicking the BCD database/track programming button (file cabinet symbol) on the main window (See "CD DATABASE" below).

There will not be a per-item description of all the features, because full on-line help is available (See "ONLINE HELP" below).


For general information about xmcd, click the help (question mark symbol) button on the xmcd main window. You can also get specific help information about each button, control, indicator, text entry area, selection list by positioning the mouse cursor over the desired item, then clicking the third mouse button. A pop-up window will appear, containing the relevant help text.


You can program xmcd to play only certain tracks, in a custom sequence. To do so, invoke the CD Database window (by clicking the CD database/track programming button on the main window). Select the desired track by clicking on the entry in the Track list, and click the Add button to add to the play sequence. Notice that the track number appears in the Program sequence text field. You can also type the track numbers, separated with commas, directly in the Program sequence field. Repeat until all desired tracks have been entered, then click the Play/Pause button (on the main window) to start the program play.

When a program sequence is defined, the prog indicator in the main window display area "illuminates". To erase the program sequence, click the Clear button on the CD Database/Program Editor window.


The CD Database feature of xmcd allows you to enter the CD artist/title, track titles, other free-form text (such as band information, lyrics, etc.) associated with the disc and tracks, and a track play program. After this information is typed in and saved to a database file, it will automatically appear on the xmcd CD Database window the next time you insert the same CD.

You must perform a "save" operation (click the Save button) after typing in the database information before ejecting the CD or exiting, or the information will be lost. If this is the first time this CD database entry is being stored, you will be asked to select a category (rock, classical, jazz, etc.) under which to classify the CD. The category is used by xmcd to determine the actual directory in the filesystem to write the database file.

You must type the CD information into the database because the CD's table of contents (TOC) contains only the number of tracks and the starting address of each track, but not the actual disc and track titles.

The CD database window should prove to be intuitive to use. You may use the on-line help system to obtain specific help information about the various buttons and items.

The CD database information is stored in text files, one per CD, in a designated directory (category). The path of this directory is CDDBDIR/CATEGORY, where CDDBDIR is the top level directory of the local CD database. CDDBDIR is typically /usr/lib/X11/xmcd/cddb and CATEGORY is the category name selected when Save is performed. See the description of XMCD_CDDBPATH in the ENVIRONMENT section below.

You may view the list of directories that xmcd will search for CD database files by clicking the About... button and viewing the pop-up information window.

The file name of each CD database entry is a hexadecimal representation of a special "magic" number computed by xmcd based on the number of tracks, track timings, and other available information about this CD. This method is used because there is no reliable unique CD identifier to be found on the CD itself (the CD standard allows for a readable IPC/barcode but very few CDs actually contain such information).

Since different pressings of the same CD may sometimes contain slightly different track timings, the resultant magic number computed by xmcd on these CDs will be different. Thus, if you load a CD that is not the same one that a CD database entry was created with (but is actually the same CD title), xmcd may not recognize it and display the database information automatically when you insert the CD. In this event, you can search the CD database and find the appropriate entry, and establish a "link" to it. To do so, click the Link button, and select the appropriate category on the popup window. Xmcd will then present another pop-up window containing a list of all CD database entries in the specified category (that has the same number of tracks as the currently inserted disc). Select the appropriate entry and a link will be made in the CD database.

The Link feature alleviates the need to type in CD database information again and avoids duplicate CD database entries.

A master CD database of hundreds of thousands of CD titles is available for Internet access. Xmcd has the ability to query a remote CDDB server host for CD database information. If your system is connected to the Internet, you can configure your xmcd client to query the server. The cddbPath parameter or the XMCD_CDDBPATH environment variable is used to configure the use of a remote server. See the ENVIRONMENT section below for details.

You may configure xmcd to communicate with the CD database server in either CDDBP or HTTP protocols. The CDDBP protocol is the standard CD database protocol developed for use by xmcd and other clients. The HTTP protocol is intended for users who are behind a firewall that allows HTTP traffic (for web access) but blocks the normal CDDBP port. Proxy servers are also supported under the HTTP mode.

You are encouraged to contribute to this database by sending CD database entries (that you typed in) to the master CD database. To do so, you click the Submit... button on the CD database/Track Program Editor pop-up subwindow. Clicking this button causes the CD database entry (associated with the currently loaded CD) to be sent to the CDDB master server. You should use this feature only if your computer is configured to send Internet electronic mail. You can send a CD database entry only after you first save it to your local CD database.

For more information about CDDB, visit the http://www.cddb.com web site for details.

While xmcd is running, the file /tmp/.cdaudio/curr.nnnn (where nnnn is the hexadecimal representation of the CD-ROM's device number) contains the device node path, CD database category and disc identifier information pertaining to the currently loaded CD. Other applications may read this file to identify the currently loaded disc.


Several environment variables are currently recognized by xmcd, and are described as follows:
This parameter is the directory path under which xmcd's configuration files, help files, and CD database files are located. The default value of XMCD_LIBDIR on Debian is /usr/share/xmcd and is set automatically.
This is used to override the cddbPath common configuration parameter, which is a list of CD database category directories to be used under $XMCD_LIBDIR/cddb. Also, remote CD database hosts can be specified.


This string will cause xmcd to search the following directories for CD database files:


You may also specify absolute path names in the XMCD_CDDBPATH entries. Example:


You may also specify a remote CD database server hosts which xmcd can use to query CD database information. The syntax is in URL form:


The protocol is either "cddbp" or "http", depending on which protocol you want xmcd to use to communicate with the remote server. The hostname can be a fully qualified host name or an IP number. The port number is optional (the default is 888 for cddbp and 80 for http ) and the path is used only in the http mode.



This is used to determine your home directory. Xmcd first tries to obtain your home directory from the /etc/passwd file. If that is not found, then it uses what is defined in the HOME environment variable. The home directory path is used by xmcd to locate the .xmcdcfg directory.


Not all CD-ROM drives support all features that appear on xmcd. For example, some drives do not support a software-driven volume control. On these drives the xmcd volume control slider may have no effect, or in some cases it is made to function as a mute control (i.e., it will snap to the full-off or full-on positions only). Similarly, the caddy lock, eject and index search buttons found on xmcd may not have any effect on drives that do not support the appropriate functionality.

The remote control feature (using the -remote option) is governed by the standard display server security mechanisms of the X window system. In order for an xmcd sender client to communicate with a running xmcd receiver client, the sender must have the appropriate access permissions to the receiver client's X display. See xhost(1), xauth(1) and Xsecurity(1) for more information. If logging is enabled, remote control activity is logged by the xmcd receiver client in the $HOME/.xmcdcfg/remote.log file for each xmcd user.




Xmcd/cda home page: http://metalab.unc.edu/tkan/xmcd/
CD database server page: http://www.cddb.com/
FreeDB database server page: http://www.freedb.org/
Xmmix home page: http://metalab.unc.edu/tkan/xmmix/


Ti Kan ([email protected])
AMB Research Laboratories, Sunnyvale, CA, U.S.A.

Xmcd also contains code contributed by several dedicated individuals. See the README file in the xmcd distribution for information.

Comments, suggestions, and bug reports are always welcome.