CDA(1) manual page
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cda - Compact disc digital audio player utility
cda [-dev device] [-debug] command
Cda is a program
that allows the use of the CD-ROM 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.
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 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).
- -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>
- Load or eject the CD.
- 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 [value#]
- If no argument is specified, this command displays
the current channel routing setting. If a value is used, then the routing
is set to the specified value. The valid range is 0 to 4, as specified below:
0 Normal stereo
1 Reverse stereo
2 Mono-L
3 Mono-R
4 Mono-L+R
- status [cont [secs#]]
- Display the current disc status, 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 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.
- 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.
Before using any function of the cda utility, you must
first ensure that the XMCD_LIBDIR environment variable is properly set
(see ENVIRONMENT below). This variable is optional in xmcd but is required
for cda.
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.
- 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(1M)
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
is a required 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, most
SCSI-1 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(1)
, wm2xmcd(1)
, X(1)
.
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.
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