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Complete List of Configuration Values used by SIGGEN progams
------------------------------------------------------------
Name sgen swgen tones siggen sweepgen fsynth smix
-------- ---- ----- ----- ------ -------- ------ ----
BUFFSPERSEC N N N Y Y Y N
CHANNELS Y Y Y Y Y Y N
DACFILE Y Y Y Y Y Y N
FRAGMENTS N N N Y Y Y N
LOADABLE_WAVEFORMS
N N Y N N N N
MIXERFILE N N N N N N Y
SAMPLERATE Y Y Y Y Y Y N
SAMPLESIZE Y Y Y Y Y Y N
VERBOSE Y Y Y Y Y Y Y
VI_KEYS N N N Y Y Y N
Configuration Value Details
---------------------------
BUFFSPERSEC The number of sound buffer fragments to play every second.
This is used to calculate the size of the buffer fragments, to
the nearest power of 2. see FRAGMENTS below for a fuller
discussion.
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 seperately
configurable oscillators used to mix the single output channel.
DACFILE The Digital to Analogue Converter (or PCM of 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
driver in the buffer fragments. If the amount of data buffered
is too much then there will very noticable 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 so that aprox.
BUFFSPERSEC buffers are played every second. Hence there will
be (FRAGMENTS/BUFFSPERSEC) seconds worth of samples buffered.
Hence if FRAGMENTS is set to 3, and BUFFSPERSEC set to 15,
there will be aprox. 3/15 = 0.2 secs worth of sound buffered
for output. On a lightly loaded fast machine this, should be
sufficient. To cover periods of heavy load or on a less
powerful machine set FRAGMENTS to 4 or 5, or set BUFFSPERSEC to
a lower value. But remember the interactive programs will
appear sluggish in responding to the keyboard.
LOADABLE_WAVEFORMS
Number of loadable waveforms allowed.
MIXERFILE The mixer device to control. This must be a real OSS
mixer device, otherwise the ioctls used will fail.
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.
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.
32000 is also used, but I forget where.
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.
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