cda - Compact disc digital audio player utility

cda [-dev device] [-batch] [-remote | -noremote] [-debug] command

Cda is a program that allows the use of the CD-ROM or CD-R drive as a full-featured stereo compact-disc player from the shell command line. It can be used interactively in line mode or visual (screen) mode, or as a script-driven utility. This is a companion utility to xmcd, a Motif-based CD audio player application for the X window system. Cda uses the same configuration and support files as xmcd.

Most of the features found on "real" CD players are available in cda, such as shuffle and repeat, and track programming functions. Multi-disc changers are also supported.

A CD database feature allows the CD artist/title and track titles, and other associated general purpose text to be displayed 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. No capability is provided to update the CD database via cda. You must use the X-based xmcd(1) utility to add or modify CD database entries.

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

Cda is designed to be easy to use, with particular care taken to make all output easily parsable by other programs.

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

Cda 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).

-batch

Signifies that cda should run in batch mode. This suppresses all interaction with the user (i.e., will not prompt the user to type anything). Batch mode is not meaningful in visual mode.

-remote, -noremote

Forces the cda client to enable or disable remote CDDB server access. If this option is not specified, then the default is configured via the cddbRemoteDisable parameter in the common.cfg file.

-debug

Causes verbose debugging diagnostics to be printed on stderr. Note that if you are running in visual mode, the stderr output should be redirected to a file, or the debug information will corrupt the screen.

Cda supports the following commands:

on

Start the cda daemon.

off

Terminate the cda daemon.

disc <load | eject | prev | next | disc#>

Load or eject the CD, or change discs on a multi-disc changer.

lock <on | off>

Enable/disable the CD disc lock. When locked, the CD cannot be ejected using the CD-ROM front-panel eject button.

play [track# [mm:ss]]

Start playback. If the track# is used, the playback starts from the specified track. The optional mm:ss argument specifies the minutes and seconds offset into the track from where to start playback.

pause

Pauses the playback. Use cda play to resume playback.

stop

Stop the plaback.

track <prev | next>

Proceed to the previous or the next track. This command is only valid when playback is already in progress.

index <prev | next>

Proceed to the previous or the next index. This command is only valid when playback is already in progress.

program [clear | track# ...]

If no argument is specified, this command displays the current program play sequence, if any. The clear argument will cause the current program to be cleared. To define a new program, specify a list of track numbers separated by spaces. To start program play, use the play command. You cannot define a new program while shuffle mode is enabled.

shuffle <on | off>

Enable/disable shuffle play mode. When shuffle is enabled, cda will play the CD tracks in a random order. You can use this command only when audio playback is not in progress. Also, you must clear any program sequence before enabling shuffle.

repeat <on | off>

Enable/disable the repeat mode.

volume [value#]

If no argument is specified, this command displays the current audio volume setting. If a value is used, then the audio volume level is set to the specified value. The valid range is 0 to 100.

balance [value#]

If no argument is specified, this command displays the current balance control setting. If a value is used, then the balance is set to the specified value. The valid range is 0 to 100, where 0 is full left, 50 is center and 100 is full right.

route [stereo | reverse | mono-l | mono-r | mono | value#]

If no argument is specified, this command displays the current channel routing setting. Otherwise, to set the routing, 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

status [cont [secs#]]

Display the current disc status, disc number, track number, index number, time, modes, and repeat count. If the cont argument is specified, then the display will run continuously until the user types the interrupt character (typically Delete or Ctrl-C). The optional secs sub-argument is the display update time interval. The default is 1 second.

toc [offsets]

Display the CD Table of Contents. The disc artist/title and track titles from the CD database associated with the current disc is also shown, if available. If an exact CD database match is not found, but the CD database server provides a list of inexact matches, then the user will be prompted to select from that list. If batch mode is active (i.e., the -batch option is used), then no such prompt will occur. If the offsets argument is used, then the track times are the absolute offsets from the start of the CD. Otherwise, the times shown are the track lengths.

extinfo [track#]

Display the disc extended information text associated with the current CD, if available from the CD database. If the CD is currently playing, then the track extended information associated with the playing track is also displayed. If a track number is used in the argument, then the track extended information text of the specified track is shown instead.

on-load [autolock | noautolock | none | spindown | autoplay]

Display, 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. If no argument is used, then the current settings are displayed.

on-exit [none | autostop | autoeject]

Display, enable or disable options when the cda daemon exits. The autostop option will cause cda to stop playback, and the autoeject option will cause cda to eject the CD. Use none to cancel these options. If no argument is used, then te current settings are displayed.

on-done [autoeject | noautoeject | autoexit | noautoexit]

Display, enable or disable options when cda is done with playback. The autoeject option causes the cda daemon to eject the CD. The autoexit option will cause the cda daemon to exit. If no argument is used, then the current settings are displayed.

on-eject [autoexit | noautoexit]

Display, enable or disable options when cda ejects a CD. The autoexit option will cause the cda daemon to exit after ejecting the CD. If no argument is used, then the current settings are displayed.

changer [multiplay | nomultiplay | reverse | noreverse]

Display, enable or disable multi-disc changer options. The multiplay option specifies that cda plays all discs in sequence. The nomultiplay option will cause cda to stop after the current disc is done. The reverse option implies multiplay, except that the disc order is reversed. If no argument is used, then the current settings are displayed.

device

Displays the CD-ROM and device information.

version

Displays the cda version and copyright information.

debug [on | off]

Show, set or unset the debug mode. If set, verbose debugging diagnostics will be printed on stderr of the terminal that the cda daemon is started from. If this is the same terminal that is running cda in visual mode, the debug information will corrupt the screen.

visual

Enter an interactive, screen-oriented visual mode. All other cda commands can also be invoked within this mode.

See xmcd(1) for a description of the device configuration requirements.

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

Start the cda daemon with the cda on command (or the F1 (o) function in visual mode). This reserves the CD-ROM device and initializes the program for further commands. All other cda functions will not work unless the cda daemon is running. The other cda commands should be self explanatory.

The off command (or the F1 (o) function in visual mode) can be used to terminate the cda daemon and release the CD-ROM drive for use by other software.

If the cda visual command is used, it enters a screen-oriented visual mode. In this mode, the status and other information available is continuously displayed and updated on the screen, and virtually all functions are available via a single key stroke.

A minimum screen size of 80 columns by 24 rows is recommended for the visual mode.

Visual mode uses the curses screen library to control the screen. It is essential that the TERM environment variable reflect the current terminal type, which ideally should have 8 (or more) function keys. Since function key definitions in terminfo descriptions are often unreliable, alphabetic key alternatives are also available.

The screen is divided into two windows: an information window and a status window. According to context, the information window displays a help screen, device and version information, disc information and table of contents, or track extended information. This window is scrollable if it overflows its allotted screen area. The status window consists of the last few lines of the screen, enclosed in a box. The first line contains the program list, or track number and offset together with volume, balance and stereo/mono information. The remaining lines contain the function keys (with their alphabetic synonymns) and the functions they invoke. These functions are highlighted when they are on, making it easy to see the current state.

Screen annotation and online help make operation self explanatory, but for reference, a list of commands follows. Alphabetic key alternatives to function keys are given in parenthesis.

?

Display help screen. Dismiss this screen by pressing the space bar.

F1 (o)

On/Off. Start or stop the cda daemon.

F2 (j)

Load or eject the CD.

F3 (p)

Play, pause or unpause.

F4 (s)

Stop.

F5 (k)

Enable/disable the CD caddy lock. When locked, the CD cannot be ejected using the CD-ROM front-panel eject button.

F6 (u)

Shuffle/Program. Pressing this key cycles through three states: normal, shuffle and program. In shuffle mode, the tracks of the CD will be played in random order. On entering program mode, cda will prompt for a space or comma separated list of track numbers, representing a desired playing order. The list should be terminated by carriage return. An empty list returns cda to normal mode. Shuffle and program mode cannot be engaged unless a CD is loaded but not playing or paused.

F7 (e)

Enable/disable repeat mode.

F8 (q)

Terminate the visual mode. If the cda daemon is running, a reminder of the fact is given and it is allowed to continue. The CD-ROM drive will continue operating in the same state. Cda may be invoked again in either visual or line mode when required.

D/d

Change to the previous/next disc on multi-disc changes.

Cursor left/right (C/c)

Previous/next track. This is only valid if playback is already in progress.

</>

Proceed to the previous/next index mark. This is only valid if playback is already in progress.

Cursor up/down (^/v)

Scroll the information portion of the screen up or down. It may be scrolled up only until the last line is on the top line of the screen, and may not be scrolled down beyond the initial position. The initial scroll position is restored when different information is displayed, (e.g., when switching to or from the help information).

+/-

Increase or decrease volume by 5%.

l/r

Move balance 5% to left or right.

Tab

Successive depressions of this key change the mode from stereo to mono, mono right, mono left, reverse stereo, and back to normal stereo.

<n> [mins secs]

Proceed to track n at mins minutes and secs seconds from the start. If mins secs is not given, start at the beginning of track n.

^l/^r

Control-l or control-r repaints the screen. This is useful if the screen has been corrupted (e.g., by operator messages sent by the wall(1) command).

The CD Database feature of xmcd is supported by cda, which allows you to display the disc artists/title, track titles, and extended information about the CD or tracks via the toc or extinfo commands of cda. In visual mode, this information is displayed automatically if available. You cannot update the CD database via cda. Xmcd must be used for that purpose.

Several environment variables are currently recognized by cda, and are described as follows:

XMCD_LIBDIR

This parameter which specifies the directory path under which cda's configuration files and CD database files are located. On most systems this is /usr/lib/X11/xmcd.

XMCD_CDDBPATH

This is used to override the cddbPath common configuration parameter, which is a list of CD database category directories to be used under XMCDLIB/cddb. See xmcd(1) for details.

Not all CD-ROM drives support all features that appear on cda. For example, some drives do not support a software-driven volume control. On these drives the cda volume and balance commands may have no effect, or may simply change the volume between full mute and maximum. Similarly, the lock, disc, index, and route commands of cda may not have any effect on drives that do not support the appropriate functionality.

$HOME/.xmcdcfg/

XMCDLIB/cddb/

XMCDLIB/config/config.sh

XMCDLIB/config/common.cfg

XMCDLIB/config/device.cfg

XMCDLIB/config/.tbl/

XMCDLIB/config/

XMCDLIB/help/

BINDIR/cda

MANDIR/cda.1

/tmp/.cdaudio/

Xmcd/cda home page: http://metalab.unc.edu/tkan/xmcd/

CD database server page: http://www.cddb.com/

FreeDB server page: http://www.freedb.org/

Xmmix home page: http://metalab.unc.edu/tkan/xmmix/

xmcd(1), cddbcmd(1), wm2xmcd(1), X(1),

Xmcd's README and INSTALL files

Xmcd web site: http://metalab.unc.edu/tkan/xmcd/

CDDB web site: http://www.cddb.com/

Ti Kan (ti@amb.org)

AMB Research Laboratories, Sunnyvale, CA, U.S.A.

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

Comments, suggestions, and bug reports are always welcome.