You wonder why it is better to have a Delfina sound card with a freely
programmable DSP instead of a card that is specialized to replay MP3 files
and to encode Dolby surround sounds? The answer is that the possibilities
the Delfina sound card provides are much more than these applications.
E.g. it can act as a great effect processor for you. This is ideal for
people with a great sound card but a poor music keyboard (like me :-).
DelfLuxe is a collection of Delfina effects such as tone generators and
filters. Most of them are already available in Assampler in a rather
non-realtime manner.
Installation:
I did not include an install script, but installation is very simple.
Extract the archive to somewhere you want. Then move
libs/delfinacontrol.library to your Libs: directory. You may also want to
assign DelfLuxe: to the delfluxe directory, then OctaMED can find the
scripts for demo songs.
Usage:
In DelfLuxe a central library called delfinacontrol.library supports a
common CLI argument template and an interface to several controling
sources. (GUI? See below)
The basic template for all DelfinaMidi(#?) programs is:
NAME/K,ALGORITHM=ALGO/K,
OMOD/K,OSOCKET/K/N,INTISOCKET/K/N,INTOSOCKET/K/N,IMOD/K,ISOCKET/K/N,
CONTROLRATE=CR/K/N,PRIORITY=PRI/K/N,SIGNALTASK/K/N
ALGORITHM, NAME
Every effect can be associated with a group of effects called Algorithm.
There is no structure, no handle that is allocated for an algorithm. It is
only the same algorithm name which makes several effects belong together.
Further it is possible to give every effect a name according to its
function. E.g. if you have an oscillator that controls another
oscillator, you could call the first oscillator a "Low Frequency
Oscillator", short LFO. Then both modules are distinguishable. If you do
not specify a NAME, the default name is derived from the effect name, e.g.
DelfinaOscillator -> NAME=Oscillator
DelfinaMoogFilter -> NAME="Moog Filter"
The name of the internal Delfina modules that are created are
concatenations of ALGORITHM, NAME and an internal name, if the effect is
build of more than one Delfina module (e.g. DelfinaMidiReverb).
Whenever a module is adressed by its name by DelfLuxe programs the module is
searched first as part of the same algorithm before it is tried to find a
module which owns this name as internal Delfina name.
E.g. in case of
DelfinaMidiEcho ALGORITHM=Forrest OMOD=Connectors ...
a Delfina module with name "Forrest Echo" is setup (because an alternative
name was left) and it is tried to connect its input to "Forrest Connectors"
which will probably not exist, thus it is connected to the global
"Connectors" module.
OMOD, OSOCKET, INTISOCKET, INTOSOCKET, IMOD, ISOCKET
A connection
[OMOD] OSOCKET --- INTISOCKET [ThisModule] INTOSOCKET --- ISOCKET [IMOD]
is setup. Socket options indicate where pipes are plugged in. This saves
you some calls to SetPipe and let you benefit from the improved module
search. (See options ALGORITHM, NAME)
CONTROLRATE
The frequency with which controling Delfina signals are checked. E.g. if
you use an Oscillator as control signal for a filter sweep, the control
rate should be the higher the faster the Oscillator moves, otherwise you
get ugly quantifying effects. (Unfortunately, although I use microHz as
timer unit, it sounds to be never faster than screen refresh. :-( )
PRIORITY
Priority of the task that checks for incoming MIDI and Delfina controling
events. If the priority is too low, the controling might be interrupted by
moving windows, starting programs etc.
SIGNALTASK
For internal use with DelfinaRunModule.
Controller
Some parameters of every effect are controlable. E.g. the filter frequency
can be controlled by the pitch bender wheel of your MIDI keyboard.
DelfinaMidiMoogFilter FREQUENCY=midi.bender:exp(110,6) ...
means that the filter frequency is controlled by any pitch bender event
that comes from some MIDI device, where the lower limit of the wheel is
mapped to 110 Hz (the unit Hz is the interpretation of the filter effect)
and the upper limit is mapped to 110 Hz * 2^6 = 7040 Hz. Thus, in the
center position of the pitch bender wheel a filter frequency of 880 Hz is
set (exponential scaling).
Now the full explaination. The controller description is divided into an
incoming and an outgoing part. Both are separated by a colon. The ingoing
part tells what source should be watched and which value range one have to
expect from it. The outgoing part tells how to map the incoming values
into effect parameters.
ingoing part
constant
The controller does not change its value. It is fixed to the one
specified on the outgoing part. This differs a little bit from the
standard scheme. E.g. constant:100 means a constant value of 100. You
can not abbreviate FREQUENCY=100 but you must write FREQUENCY=constant:100
instead, sorry!
delfina
delfina.LFO.0 addresses the output signal at socket 0 of the Delfina
module LFO (either in the same algorithm or globally)
midi
midi.keyboard(min,max) - holds the key number of the currently pressed key.
The range of keys from min to max is mapped to the outgoing range,
but also keys outside this range are mapped.
midi.keyboard(48,60):exp(523.25,1) maps the keys from a specific C to
the next C (don't ask me for absolute octave numbers)
to the corresponding frequency
midi.keyboard(48,60):exp(523.25,-1) reverse the key order :-)
midi.keyboard(48,101):exp(523.25,1) enables you to play Steinberg's
53-tone music B-)
midi.velocity - the force with which you have pressed the key
midi.aftertouch - pressure on a key when it is already down
midi.bender - the pitch bender wheel
midi.modulation - the modulation wheel
midi.vectorx - x component of Vector Control joystick (Yamaha SY35)
midi.vectory - y component of Vector Control joystick
midi.volume - volume of the sound (never received this event)
midi.sustain - state of the sustain pedal (never tested)
midi.controller.$0A(0,$80) - the MIDI controller with number $0A (10 = pan
due to the MIDI specifications) which can have values from 0 (inclusive)
to $80 (exclusive), at least I assume so ;-)
midichannel
E.g. by replacing midi by midichannel.3 you can make the effect to listen
to events on MIDI channel 3 instead of listening to all channels.
outgoing part
lin(0,1)
means linear scaling from 0 to 1. Thus
VOLUME=midi.velocity:lin(0,1)
let you interpret the key press force of the MIDI keyboard as volume for
some effect.
exp(440,3)
means exponential scaling from 440 to 3 octaves higher, i.e. 440*2^3 = 3520
E.g. it would sensible to map 12 keys from the keyboard to 1 octave.
Effects
Every of the following programs supports one effect and has additional CLI
options for their controllers. I am a bit lazy to explain all controllers.
I hope you can guess their meanings easily.
DelfinaMidiAllpassCascade
A cascade of ORDER all passes, which can be used to simulate phasing
effects from analogue synthesizers.
DelfinaMidiAmplifier
A simple amplifier.
DelfinaMidiBlockResample
Blockwise resampling. Unfortunately the periodic clicking becomes faster
the more you move away from 1:1 resampling.
DelfinaMidiComplexFilter
Band pass like filter where each stereo channel influences the other.
DelfinaMidiEcho
Repeated echo. To minimize the need for allocation of echo buffers (which
would require a buffer flush at each reallocation) you have to specify a
fix maximal possible delay and the real delay is measured as ratio of this
and can be controlled.
DelfinaMidiFilter1stOrder
Simple filter with high pass and low pass output on different sockets.
DelfinaMidiGetAmplitude
Envelope follower.
DelfinaMidiLimit
Limits each elongation (sample). Creates the fuzz distortion effect.
DelfinaMidiMoogFilter
A cascade of ORDER low passes which are fed back to obtain band pass
characteristic. This is a filter of Moog's synthesizers.
DelfinaMidiMultiplier
An amplifier where the second input signal is the volume control. Can be
used as ring modulator.
DelfinaMidiNoise
Noise generator with built-in quantification.
DelfinaMidiOscillator
Tone generator with optional linear interpolation. There are some
waveforms in 32-bit signed words format in the waves directory which are
ready to be loaded into the oscillator. Feel free to create new forms!
DelfinaMidiReverb
A reverb made of some short echos. Very memory and time consuming. Will
probably force the Delfina to switch back to lower sample rates.
DelfinaMidiUniFilter
The universal filter provides high pass, band pass, low pass and band
limit at its four output sockets.
DelfinaMidiVocoder
A multi-channel vocoder. Don't work. The analysis filters don't seem to
work the way they should. I chose the ComplexFilter because it is the
fastest. Every other filter will slow down the process to unacceptable
sample rates or number of channels :-(
DelfinaRunModule
Runs another DelfinaMidi(#?) effect program in the background, but waits
until the effect is completely set up. This is necessary for batch scripts
where every module assumes that the module already exists where it wants to
connect to.
Attention! Improper use of DelfinaRunModule will crash your machine! I
did not found a way to make the whole thing really safe. Because the user
may accidentally start a program that is not an effect program,
DelfinaRunModule may wait infinitely. To avoid this you can break
DelfinaRunModule with CTRL-C. But make sure that the started program will
never try to tell DelfinaRunModule about its successful setup after you
quit DelfinaRunModule, or the machine will crash as soon as it try so.
DelfinaQuitAlgorithm
Sends a CTRL-C to all programs that are associated with the algorithm
name.
DelfinaListContexts
Similar to Delfina:ListMod, but lists all effects that run with
delfinacontrol.library currently.
DelfinaCreateWaves
The program which generated the files in the waves directory.
Additional tools
To be able to manage situations you got by accidentally starting programs
with wrong options etc. you should be familar with AmigaDOS commands Status
and Break, or alternatively with the system monitors Scout, ARTM
(AmigaRealTimeMonitor).
Examples:
To get the effect examples running you should plug a sound source, e.g.
microphone, synthesizer line output, radio etc. into your Delfina card.
(I assume that the Delfina card is all the time plugged into a HIFI
amplifier on the other side. Thus we skip this step. :-) For the MIDI
controlled effects, you should additionally connect the MIDI output of some
keyboard with the MIDI interface in your Amiga. Then run some of the
scripts in the "s" directory or play one of the OctaMED modules which will
start some of the (#?)NoCtrl scripts by themselves. These scripts will
fail to run without OctaMED, because they will open an requester on the
OctaMED screen.
Technical background:
Streaming
As Assampler the delfinacontrol.library and DelfLuxe are developed with
Cluster (= Modula II deluxe). The delfina code is written with a56, the
standard DSP 56000 assembler for Delfina cards.
The delfinacontrol.library is a temporary solution until this or the next
Amiga system will have a very sophisticated streaming engine build into.
This would enable us to process several signals coming from MIDI (wheels,
keys), sampled sounds (from hard disk, memory, microphone), user input
(mouse move, joy stick), synthetic sources (noise, oscillator from delfina,
Assampler). delfinacontrol.library is quite limitted in this aspect, e.g.
it is not possible to mix the two control signals "pitch bender" and "key
pitch" to create a tone controlled by MIDI keyboard and the pitch bender
wheel.
GUI
A GUI is not supported, unless you consider mus/misc/DelfSetPipeMui as
that. A nice GUI for the Delfina effects would be Assampler, but
integrating DelfLuxe into it would mean to blow up Assampler or to
completely restructure and modularize it. The latter is preferred way, but
may not come reality on the classic Amigas.
Exceptions
Exceptions are simply written to standard output (your CLI in most cases).
It's one of the things I feel to be limitting more and more in the classic
AmigaOS that it do not support an exception throwing and catching system.
Thus all languages that support exceptions have to take care not to skip OS
cleanup code when throwing an exception. That's why one do better if one
writes code in a level of plain C. :-(
Support site:
http://www.assampler.de (german)
http://www.assampler.com (english)
This is the support site for Assampler, another sound synthesis project of mine,
but its site is also used for the Delfina effects now.
Mailing list:
http://www.yahoogroups.com/subscribe/assampler
http://www.yahoogroups.com/group/assampler
Again this mailing list is mainly addressed to people interested in
Assampler, but because of very low traffic and the similar topic, you are
welcome to join it, if you are interested in Delfina effects.
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