Provided by: siggen_2.3.10-7_amd64 
NAME
siggen.conf - the siggen configuration files
SYNOPSIS
siggen.conf
DESCRIPTION
As from siggen version 2.3 onwards a versatile configuration file scheme has been
introduced. It allows parameters for the siggen programs to be specified either across the
board, or specifically for particular programs.
Three possible configuration files can be used: a LOCAL config file (usually in current
directory), a HOME config file in user's $HOME directory and a GLOBAL config file.
All the programs are compiled with the names of the config files built in. The filenames
are set in the config.h header file and can be changed. The LOCAL and GLOBAL config files
are specified by the settings of:
LOCAL #define DEF_CONF_FILENAME ".siggen.conf"
GLOBAL #define DEF_GLOBAL_CONF_FILE "/etc/siggen.conf"
And can be set to any file name or to NULL to disable the file. The HOME config filename
is created using the $HOME environment variable and the DEF_CONF_FILENAME together, i.e.
using the above, the HOME config file for a user whose home directory is at /home/jj,
would be
HOME /home/jj/.siggen.conf
The config files do not have to exist. If they exist and are readable by the program they
are used, otherwise they are simply ignored.
The config files are always searched for configuration values in the order LOCAL, HOME,
GLOBAL. This allows a scheme where the sysadmin sets up default config values in the
GLOBAL config file, but allows a user to set some or all different values in their own
HOME config file, and to set yet more specific values when run from a particular
directory.
If no configuration files exist, the programs themselves provide builtin default values
(see config.h etc), and most of these values can be set by appropriate command line
switches and flags.
CONFIGURATION VALUES
A configuration value has a name and a value, and values for all programs are set by
simply entering a line in the appropriate config file where the first word is the name,
followed by arbitrary spaces/tabs, followed by the value. The value is all the rest of
that line. e.g. to set the global default samplerate of 44100 samples per sec, the
following line would be entered in the GLOBAL config file:
SAMPLERATE 44100
Config value names are case insensitive.
A config value can be set for a specific program, by prefixing the config value name with
the program name and a ':'. e.g. to specify a samplerate of only 8000 samples per sec for
the tones program enter
TONES:SAMPLERATE 8000
in the relevant config file. If both lines above were in the config file, all programs
except tones would use a samplerate of 44100, and tones would use 8000.
You do not have to specify all configuration values in the config files. If a particular
value is missing, the programs will simply use their builtin defaults (see config.h etc).
Configuration values set by command line switches or flags take precedence over values in
any of the config files.
Beware the programs do not have their 'name' built-in, but use the name they were invoked
by. So if you change the name of a program, remember to change the config file
entries. However this does means that by using links to a program, it can be made
to pick up a different set of configuration values, depending on the name it is
invoked by.
EXAMPLE CONFIGURATION FILE
A sample config file is provided in ".siggen.conf" in the distribution. This may also be
at /etc/siggen.conf . Any line whose first non-whitespace character is a '#', is a comment
line and is ignored.
WHAT CONFIGURATION VALUES ARE THERE?
Not all of the siggen programs use all the values described here. See the relevant man
page for which values are used by which programs.
CHANNELS
In all programs except tones and fsynth, channels specifies the number of output
channels to use, i.e. 1 for Mono and 2 for Stereo.
For tones, channels specifies the number of 'voices' on which tones can generate
different waveforms before mixing them into the one output channel.
For fsynth, channels specifies the numbers of separately configurable oscillators
used to mix the single output channel.
DACFILE
The Digital to Analogue Converter (or PCM or DSP) device on which to output the
generated samples. This must be a real OSS PCM device, otherwise the ioctls used
will fail.
FRAGMENTS
The number of Audio Buffer fragments to configure in the driver. The interactive
programs respond to changes made to parameters from the keyboard immediately, but
data will be buffered in the driver in the buffer fragments. If the amount of data
buffered is too much then there will very noticeable delays before the output sound
is altered. Against that, insufficient buffering may mean that there is not enough
data buffered for output to cover the time when other processes are being run by
the scheduler. The programs set the buffer size to the nearest power of 2 to give
aprox. 100millisecs of sound. Hence if FRAGMENTS is set to 3, there will be aprox.
0.3 secs worth of sound buffered for output. On a lightly loaded fast machine this,
or 2, should be sufficient. To cover periods of heavy load or on a less powerful
machine use 4 or 5. But remember the interactive programs will appear sluggish in
responding to the keyboard.
SAMPLERATE
The number of samples per second to use. If output is to the DAC then the DAC
device is set to output samples at this rate.
BEWARE: not all cards can support all samplerates. SoundBlasters are fairly
flexible in this respect. Other cheaper cards are not. Indeed some cards can only
handle a very restricted set of related samplerates e.g. 11025, 22050, 44100 &
8000, 16000, 32000, 48000. When writing to DACFILE all programs will attempt to set
the samplerate given, but use the actual samplerate the device used. Use the
verbose command line flag to check actual samplerates used.
Some common samplerates used are:
8000
is the samplerate used in the phone system with 8 bit samples, and is adequate for
voice range frequencies.
44100
is the samplerate used in audio CDs
48000
is the samplerate used in DAT systems, I think, and for much professional kit.
32000
is also used, but I forget where, minidisc?.
In general, the higher the samplerate the larger the memory and processing
requirement, but the higher the frequency range and the more accurate the signals
generated.
SAMPLESIZE
Number of bits per sample. Only two values are allowed currently, 8 or 16.
8 bit samples are unsigned, with decimal value 128 being the ´zero´ level.
16 bit samples are signed little endian values, i.e. the least significant byte comes
before the most significant byte either in a file, or in the byte stream to an
output device.
If samplesize if left completely unspecified, then all programs will attempt to do
16 bit samples to DACFILE, and if that isn't possible will do 8 bit samples. Or if
writing to a file, 16 bit samples will be written.
VERBOSE
sets verbosity level.
0 is quiet
1 is be a bit verbose (equiv. to -v switch)
2 is be very verbose (equiv. to -vv switch)
VI_KEYS
if set to a non-zero value, then the VI cursor moving keys "HJKL" are enabled.
SEE ALSO
sgen(1), swgen(1)
BUGS
COPYING
Copyright 1995-2008 Jim Jackson
The software described by this manual is covered by the GNU General Public License,
Version 2, June 1991, issued by :
Free Software Foundation, Inc.,
675 Mass Ave,
Cambridge, MA 02139, USA
Permission is granted to make and distribute verbatim copies of this manual provided the
copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the
conditions for verbatim copying, provided that the entire resulting derived work is
distributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another
language, under the above conditions for modified versions, except that this permission
notice may be included in translation instead of in the original English.
AUTHOR
Jim Jackson
Email: jj@franjam.org.uk