SuperCollider 3 Server on Linux History Architecture Server - - PowerPoint PPT Presentation

SuperCollider 3 Server on Linux

• History
• Architecture
• Server
• Language
• SCEL
• SCUM
• Further Development
• Resources

History

• James McCartney developed SuperCollider on Mac

OS 9 and OS X:

– Synth-O-Matic (1990) – pyrite: MAX object – SuperCollider version 1 (1996), version 2 (1998),

version 3d5 (2000)

– SuperCollider 3 Server (2002)

• Linux:

– alpha port of the server (2002) – alpha port of the language (2003) – first fully functional version in November 2003

• Windows port of the server by Ross Bencina

Architecture

• Client-Server-Model
• Server application (scsynth) provides sound synthesis

facilities

• Client application (sclang) provides high-level

abstractions for communicating with scsynth

• Asynchronous communication via TCP/UDP and

OpenSoundControl (OSC) messages

• Client/Server may reside on the same machine or on

different hosts in a LAN

OpenSoundControl (1)

• Protocol for inter-application communication
• Developed at CNMAT/Berkeley
• Transport-independent
• Hierarchical, extensible address space
• Packet-based, stateless
• Packet types

– Bundle: contains timestamp, messages and other

bundles

– Message: carries actual information

• Data types: int32, float32, string, blob (untyped binary

data)

OpenSoundControl (2)

• Anatomy of an OSC message:

'/oscil/1/freq' 'f' 444.1

padded address string padded type string 32 bit float (network byte order)

Server (Overview)

• Performs DSP computations and manages resources

(synths, buses, buffers, etc.)

• Core features:

– small, efficient, portable – embeddable by linking to libscsynth – complete OSC command set – client application independent – JACK driver backend on Linux

Synthesis Tree

• Synthesis modules are part of a tree that defines order
• f execution
• Nodes are referenced by an integer identifier
• Node types

– Group: Container for nodes (linked list) – Synth: synthesis graph of unit generators (Ugens)

• Vertices define containment relationship

Nodes

• Groups contain groups and synths
• Top level group with id 0
• Nodes in a Group can be controlled simultanously
• Synths are a collection of UGens
• Created from synth definitions
• Connected through global control and audio buses
• Local buses allow modular realization of recursive

synthesis techniques

UGens, Synth Definitions

• UGen definitions are loaded from plugins

– Currently SuperCollider includes about 300 UGens

for building synthesis graphs

– UGen types (incomplete):

• I/O to and from buses, files
• Delays
• Oscillators
• Low frequency control
• Filters
• Frequency domain processing
• Triggers
• SynthDefs are named templates for creation of synths

– Binary file format

Buses, Buffers

• Buses are global arrays of scalar control and audio

values for synth interconnections

• Indexed by integers beginning at 0
• Lowest numbered audio buses are read from and

written to by the audio hardware

• Buffers are tables of floating point values
• Manipulation even while synthesis is running:

– allocate, free – read from or write to a soundfile – fill using variety of functions

• Used for wavetables, sample buffers, delay lines, FFT

buffers, etc.

Synthesis Tree

Top 0 Instruments 1 FX 2 Mix Buses Output Buses DAC Synth 1001 Synth 1002 Reverb 1003 Mixer 1004

Language (Overview)

• Object oriented language with many features applicable

to composition and performance

• Incorporates ideas from Smalltalk, Ruby, APL, ...
• Core features:

– Virtual machine model with byte compilation – Constant time method lookup – Realtime garbage collector – Dynamically typed – Closures – Routines (restartable functions, “coroutines”) – ALSA sequencer support on Linux

Object Model

• Object model similar to Smalltalk's:

– single inheritance – root class Object – method invocation by sending messages

• Notable differences:

– class definitions cannot be added at runtime – global method lookup matrix, similar to C++ vtables – syntax closer to C than Smalltalk

Routine({ #["Hello", "SuperCollider", "world!"].do({ |s| s.postln; rrand(0.5, 2).wait; }); }).play;

SynthDefs

• SynthDefs (synthesis graph definitions) are created by

evaluating UGen graph functions

• UGen graphs are optimized and compiled into a binary

representation

• The compiled SynthDef is loaded into the server while it

is running

SynthDef("whirl", { | out = 0, gate, panfreq | var freq, env, zout; freq = LFSaw.kr(0.3, 0, 24, LFSaw.kr([8, 7.23], 0, 4, 80)).midicps; env = EnvGen.ar( Env.asr(1.0, 1.0, 2.0), gate, levelScale: 0.04, doneAction: 2 ); zout = CombN.ar(SinOsc.ar(freq, 0, env), 0.2, 0.2, 4); Out.ar(out, Mix(Pan2.ar(zout, SinOsc.kr(panfreq)))); }).send(Server.default);

Proxy Objects

• Proxy Objects are a means of creating nodes on the

server and controlling them through objects in the language proper

• Implicit or explicit resource ID management
• Proxy classes for

– Groups – Synths – Buses – Buffers

x = Synth(“whirl”, [\gate, 1, \panfreq, 1]); x.set(\panfreq, 0.3); x.release;

Streams

• Streams represent finite or infinite sequences of values

(lazy evaluation)

• Important messages:

– next – reset

• Routines are functions that can return a value and be

resumed from that point

• Streams create a new Stream when sent a

– binary message, e.g. + – iteration message, e.g. select

• By default any object represents an infinite sequence of

itself

Patterns

• Patterns are template specifications for creating

Streams

• Streams are created from Patterns by sending the

asStream message

• Patterns can be nested
• Common Patterns:

– Pfunc, Prout: Functions and Routines – Pseq: sequence – Prand, Pshuf: random selection – Pn: looping – Pcollect, Pselect, Preject: filters

Events

• Events are a collection of parameters, mapping

symbols to values

• Hierarchical parameter models for pitch and amplitude
• EventPlayers realize an Event, e.g. by

– creating a Synth with initial parameters – setting parameters of a running Node

• Pbind binds symbols in each Event to values obtained

from patterns

• EventStreamPlayers are created by sending a pattern

the asEventStreamPlayer message

• EventStreamPlayers can be started, stopped, paused

and resumed

Scheduling

• Clocks evaluate functions in a timed fashion
• Return value is interval to next invocation
• Schedulable objects include:

– Functions, Routines, Streams – Patterns (EventStreamPlayers)

• SystemClock

– singleton class – time base: seconds

• TempoClock

– each instance runs in a high-priority thread – instances maintain their temporal relationship

accurately over a long period

– time base: beats, tempo: beats/second

Add-On Libraries

• Additional libraries extend SuperCollider's core

functionality, e.g.

– JITLib: proxy spaces, live coding – BBCut: algorithmic break beat cutting

SCEL

• SCEL (SuperCollider Emacs Lisp) is a comprehensive

IDE for working with SuperCollider on Linux

• sclang-mode

– syntax colorization – automatic indentation – autocompletion for symbol names and method

arguments

• Interpreter interface

– code evaluation – class and method definition browsing – RTF help file access – Document manipulation from SuperCollider code

SCUM (Overview)

• SCUM (refuse; recrement; anything vile or worthless), GUI

classes for SuperCollider

• Core features:

– lightweight – portable – flexible layout management – OpenGL integration

• Currently runs on Linux using FLTK for

– drawing – event handling – window management – OpenGL contexts

SCUM Examples

• Server Panel
• Simple sequencer

Further Development

• Completion of GUI classes on Linux

– Multislider – Envelope editor – Plot view

• Visualization facilities:

– Integration of Christophe Costigan's OpenGL

bindings

– Canvas view

• Integration of HID event sources

Resources

• James McCartney's homepage

– http://www.audiosynth.com

• Sourcefourge page

– http://supercollider.sourceforge.net

• Linux page on the Swiki

– http://swiki.hfbk-hamburg.de:8888/MusicTechnology/478

• Mailing lists

– http://www.create.ucsb.edu/mailman/listinfo/sc-users – http://www.create.ucsb.edu/mailman/listinfo/sc-dev

• SCUM sources

– http://www.cs.tu-berlin.de/~kerstens/pub