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NAME

       gom - a generic audio mixer (supports: OSS and derivatives)

SYNOPSIS

       gom {OPTION}

VERSION

       This manual page was distributed with gom 0.30.2 (31 May 2004).

DESCRIPTION

       gom  is  a  command  line  mixer  manipulation program including a minimal, yet fully functional internal
       ineractive text based interface.

       Currently, there is also an internal  X  (xview)  interface,  but  it's  not  well  maintained  and  will
       eventually be removed when a proper alternative is available.

       At  the  moment,  gom  only  supports the Open Sound System (OSS) and its derivatives (OSS/Lite, OSS/Free
       (these two are obviously obsolete), the new Linux Sounddriver, ...).

       gom tries to provide a complete and convenient interface for all kind of audio mixer manipulation.  gom's
       facilities  include  sound  driver (compile time) and sound card (run time) independence, arbitrary mixer
       selection, loading and saving of mixer settings, volume fading, verbosity-level driven output, "Un*x-like
       scripting support", etc.

       Apart  from the exhaustive command line interface described here, gom has a built-in interactive terminal
       interface (that I call gomii, gom interactive interface) using  ncurses.  It  supports  adjustable  (this
       includes  disabling)  real time updating. The gomii is not explained in this manual page; please refer to
       the specific online help when using it. However, the gomii's handling should be obvious, and actually  it
       "tries to resemble" the command line options.

       There  is also one more gomii for X using the xview toolkit. However, gom needs to be especially compiled
       to include this, and it is intended to be replaced eventually by  some  frontend  for  X  using  the  gom
       binary.

       And  remember: gom is spelled g-o-m, but pronounced backwards for compatibility reasons. Its real, actual
       and recursive title is gom, GOM is nOt yet another Mixer (for reasons beyond the scope of this manual).

CONFIGURING GOM

       There is no mandatory configuration for gom; it runs fine just as it is, without any configuration. I.e.,
       for  senseful  use  without  configuration, one always needs to (at least) specify the mixer to use.  For
       example:

       gom --device=/dev/mixer2 --mute-all

       However, you can configure gom a) for the system and b) for an individual user; each  user  configuration
       is  preferred  in favor of the corresponding system configuration. In fact, the routine for loading _any_
       option file is to 1st try the user file, then the system file, and else fail.

       To configure, you should use the script gomconfig(8) (or most likely gomconfig --force ) that comes  with
       the distribution -- using it as root will change the system configuration, normal users will change their
       own configuration. You may well skip the rest of this chapter if you do so.

       All configuration files for gom are simply gatherings of command line options to gom  (where  some  files
       are restricted to certain options). Please see "--get-options" below.

       The configuration files are (replace the "~/.gom" with "/etc/gom" for the system configuration):

       ~/.gom/conf.default_mixer
              Loaded on every startup of gom. Restricted to: "-d". Provides implicit opening of a mixer device.

       ~/.gom/conf.initialize
              Loaded  with  the  option  '-O, --originate, --initialize'. Unrestricted.  Provides creation of an
              initialization routine, even for multiple mixers.

       ~/.gom/conf.gom
              Loaded on every startup of gom. Restricted to '-v, -q, -F, -U'.   Provides  implicit  creation  of
              certain bevaviours. Discouraged.

       ~/.gom/<mixer-device>.<name>
              These  file  are  accessed simply by their <name> when <mixer-device> is opened. See --get-options
              below.

TERMINOLOGY, PHILOSOPHY

       A mixer is a set of channels (e.g. vol, line, cd). Each channel has a set of volume channels (e.g.  left,
       right), and optionally a recording source flag.

       The  evaluation  which  channels  are available, and, for an available channel, which volume channels and
       which flags are available on that specific channel, is being done at runtime; this  is  sound  card,  and
       possibly sound driver dependent.

       Thus,  there are sound driver supported channels and specific sound card supported channels.  gom --info-
       all shows all sound driver supported channels, plus indicating their specific availability.

       Up to the time of this writing, the only sound driver supported  is  OSS  (Open  Sound  System)  and  its
       derivatives.  This  driver exists for a variety of platforms and in various flavours (especially, the new
       Sounddriver of Linux is a derivative of OSS).  (Remark: Gom's point of view  on  how  a  "generic"  mixer
       should  look  like  may  be  strongly influenced by the OSS API; however, the author feels that this view
       might not (yet) be absolutely generic). At the time of this writing, OSS  supports  17  channels,  and  a
       maximum of two volume channels per channel (i.e., only "mono" or "stereo").

       Of  course, as gom depends on the sound driver installed on the system, its proper installation (which is
       naturally not covered here) is mandatory for gom (as for any other sound-using program).

OPTIONS

       Options can be given in arbitrary order or amount; they are computed in  sequence  from  left  to  right.
       Default values (if any), are given in [].  For boolean arguments, "1" means on, "0" means off.

       Note that for options with _optional_ arguments, these must be gi ven like "gom -G<file>" (or "gom --get-
       settings=<file>" resp.) ra ther than "gom -G <file>" (or "gom --get-settings <file>" resp.).   Otherwise,
       they will be ignored (or, at least with my implementat ion of getopt;).

       Configuring options:

       -d, --device, --mixer <argument>
              [  **no  mixer**  ]  Set  mixer special device file to <argument>.  If the new mixer is valid, the
              current mixer --if any-- will be closed and the new mixer opened. Current channel, current channel
              volume, the channel lock setting and the snapshot will be resetted to defaults.

       -c, --channel <argument>
              [first  available  channel]  Set current mixer channel to <argum ent>. The channel may be given as
              number or as name.

       -C, --volume-channel <argument>
              [first available volume channel on current channel] Set volum e channel on current  mixer  channel
              to <argument> (e.g., for s tereo, 0 means left, 1 means right volume).

       -k, --lock <argument>

       -K, --lock-all <argument>
              [1]  Lock  or  unlock  current  or  all  channel(s).  Locking means s yncing of the stereo volumes
              (balance) for all volume setting s gom might do -- this doesn't  change  any  volume  settings  by
              itself (i.e., it doesn't auto-balance). Thus, a locked channe l might have unbalanced volumes.

       -F, --fade-interval <argument>
              [5] Set fade interval to <argument> seconds. See --fade-to-lo udness.

       -U, --refresh-interval <argument>
              [30] Set gomii refresh (update) interval to <argument> second s (zero disables).

       -W, --write-config, --save-config
              This option is obsolete since version 0.29.10.

       Setting mixer options:

       -l, --loudness, --volume <argument>
              Set  current volume channel on current channel to <argument>.  If the argument is being given with
              a leading "+" or "-", the given value will be added or substracted, respectively, from the current
              value. The allowed range is from zero up to a sou ndcard driver dependent maximum.

       -r, --record <argument>
              Set recording for current channel on or off.

       -R, --record-single
              Set recording for current channel on and disable all other re cording sources.

       -L, --fade-to-loudness, --fade-to-volume <argument>
              Like --loudness, but fade to the new volume within a time giv en with --fade-interval.

       -m, --mute

       -M, --mute-all
              Mute current or all channels. Muting means setting all channe l volumes to 0.

       Mixer settings options:

       -G, --get-options, --load-options, --get-settings, --load-setting
              Get  options  from/to file <argument>. If no argument is given, the default file (named "default")
              is used. Non-absolut given filenames will be expanded  to  "<mixer-device>.<argument>",  and  then
              first  searched for in the user and -- if this fails -- in the system configuration directory. Any
              free-form files with gom one-character command line options in any lines starting with a dash  (in
              column zero) will make sense to this option.

       -S, --save-settings [<argument>]
              Save  mixer  settings to a free-form option file; for the file name, the same rules as for loading
              option files apply, except that only the user configuration dir will be used.  Files  with  thusly
              expanded  filenames  will  be  silently overwritten; other files never. When saving, care is being
              taken that the "last recording source error" can't occur when loading  these  options  (and  maybe
              there  are other reasonable side effects apart from the pure mixer settings (e.g. channel locking,
              current channel)). The bottom line to these load/save options is that you can easily save new  and
              load predefined mixer settings from anywhere.

       -z, --snapshot-settings

       -Z, --unsnapshot-settings, --restore-settings
              [mixer settings after opening a new mixer] Snap- or unsnapsho t to/from current mixer settings.

       -O, --originate, --initialize
              Load  the  options  file  "initialize";  all  options  are  allowed in this file. This is meant to
              initialize mixers. For example: "-d/dev/mixer0 -G -d/dev/mixer1 -G". This would load  the  default
              settings file for both the mixer0 and the mixer1 device.

       Informational options:

       -t, --info
              Display current channel information.

       -T, --info-all
              Display overall information.

       -V, --version
              Display version information.

       -w, --copyright, --copyleft, --license, --warranty
              Display copyright/license/warranty information.

       -h, --help

       -H, --help-verbose
              Display  this  help  normally or verbose; both helps are still d ependent on the current verbosity
              level (i.e., higher verbosi ty levels might still show more; "gom -v0 -H" and "gom  -h"  pr  oduce
              the same output). For the normal verbosity level, these are reasonable macros.

       Special options:

       -e, --execute <argument>
              Execute the shell command <argument>.

       Command line only options:

       -Y, --ignore-config
              Skip  all  automatically  loaded  configurations files; this must be given before any other option
              (except q (quiet) or v (verbose)).

       -i, --interface, --gomii <argument>
              Explicitly start up a build-in gomii (<argument>=t: terminal gomii, <argument>=x: X gomii).

       -v, --verbose [<argument>]
              [NORMAL] Set output verbosity to <argument> (number,  the  high  er,  the  more  verbose).  If  no
              argument is given, the level will be increased by 1.

       -q, --quiet, --silent
              Set output verbosity to QUIET (only error / error help messag es).

       -p, --pure, --print <argument>
              Pure-print  the current channels value given by <argument> to stdout (<argument>=l|r, according to
              one character options).  Useful for getting values "into"  scripts  together  with  the  --  quiet
              option.

       -x, --extract-settings
              Extract  all  mixer  settings  as  a  gom  option line to stdout (e.  g. for "setting=`gom --quiet
              --extract-settings`" and "gom -- quiet $settings" later in a bash script).

       -I, --read-stdin
              Read options from stdin (until EOF).

ENVIRONMENT

       HOME used as prefix for the configuration directory .gom/ for a non-root user.

FILES

       /etc/gom/ system configuration directory (user root).

       $HOME/.gom/ user configuration dir (all non-root users).

       Files inside the configuration directory:

       conf.default_mixer option file for default mixer (loaded on startup).

       conf.gom option file (loaded on startup).

       conf.initialize option file for initialization (loaded via --initialize).

       <mixer-device>.default default options file for <mixer-device> (loaded with --get-options).

       <mixer-device>.<name> mixer settings that can be easily accessed just by <name>
              with --get-options=<name> when <mixer-device> is open."

DIAGNOSTICS

        Exit status is 0 if no errors were detected while running gom; it is greater  than  0  if  one  or  more
       errors were detected. This should be interpreted as warning, not necessarily as failure.

       (The  amount  of  detected  errors  will  be printed out if the verbosity level is VERBOSE or higher; the
       warning exit status is currently always 2, but this may change).

EXAMPLES

       (This section is incomplete and most likely confusing ;).

       1. gom as system startup

       2. gom as user startup

       3. gom in a running session

       4. gom in scripts

       5. Some more detailed examples

       gom --interface=t, gom -it
              Interactively manipulate mixer settings with the terminal gomii.

       gom --get-settings, gom -G
              (e.g. when you log in as user). Loads user's default options file.

       gom --get-settings=cd, gom -Gcd
              Loads options file "cd" (most likely a setting for playing cds).

       gom -d/dev/mixer0 -M -d/dev/mixer1 -l100
              First, mute mixer 0, then set the volume of the first channel on mixer 1 to 100.

       gom -M -c vol -l 90 -c pcm -l 90 -e bplay super.voc -Z
              Plays the sample super.voc on channel 4=pcm with all  other  channels  muted,  restoring  original
              mixer settings afterwards.

       gom -ix -e <any_sound_player> -Z
              Plays  any  sound,  interactively setting the mixer before with the X gomii and restoring settings
              afterwards.

AUTHOR

       Copyright (c) 1996-2004 Stephan Alexander Sürken <absurd@olurdix.de> GPL.

       The X gomii of the gom package is also Copyright (c) Hannu Savolainen 1993 (as it is originally based  on
       "xvmixer" by Hannu Savolainen).

       The gom package is licensed under the GPL (GNU General Public License).  The files "README" and "COPYING"
       in the original distribution contain the exact terms.

SEE ALSO

       gomconfig(8)

       Information about OSS can currently (1999 August 18) be found at "http://www.opensound.com/".

KNOWN BUGS

       Gom does not detect recursion in option files (e.g. by adding a "-Gcd" to an options file named "cd").

       There must always be at least one recording source, so when writing option files for gom "by hand", first
       put  all  to-be-active  recording  sources  on,  then  all to-be-inactive recording sources off, else one
       recording source might not become inactive in unfortunate  circumstances.  Mixer  settings  automatically
       written by gom are saved in this manner.

       The  mixer  settings  files  may  be  inconsistent  between different sound drivers (i.e., if the channel
       numbering is different).

       Loading settings from a options file that was saved from a different mixer may lead to  errors  (if  some
       option  is  not available on the current mixer), or to silently not-setting of newly available options of
       the current mixer; saving mixer settings with the mixer name as prefix since 0.29.99 avoids this at least
       for not explicitly given mixer settings file names.

       The "text blocking output" cuts words (true, too, for the OPTIONS section of this manual page).

       X gomii bugs:

       The  X  gomii has some "bugs" due to xview and/or the lack of documentation available for the author (all
       the rest of this section):

       The X gomii creates its display objects with xview, but doesn't check  for  allocation  errors.  I  guess
       xview somehow handles this ;).

       The X gomii's scroll window displays in a non-fixed font.

       Some  placements  in  the X gomii are still static; it could imagine that the display might look a little
       bit screwed up if you use a different configuration than mine (e.g. a different font).

       Xview, in general, "seems to be a little bit unstable" (the author itself  locked  all  his  major  input
       devices (i.e., mouse & keyboard (you should be so clever to have some other means to access your computer
       when programming xview ;)) several times by using xview applications  under  X  (not  necessarily  the  X
       gomii) for whatever unknown reasons (and without being able to reproduce the bug properly). (()())

KNOWINGLY NO BUGS

       If  starting  gom  results  in loading and initializing the kernel sound driver (e.g. if the sound driver
       gets kerneld-autoloaded under Linux), the sound card's settings are set to the driver's  default  by  the
       driver  itself.  gom has nothing to do with these defaults and doesn't change any settings -- any program
       using the sound driver in that situation would have the same effect.