Skip to main content

A synthesis framework using csound

Project description

Introduction

The core of this package is the Engine class, which wraps a csound process and allows transparent control over all parameters, while providing sane defaults. It uses the csound API to communicate with a running csound instance. All audio processing is run in a separate performance thread.

from csoundengine import *
# create an Engine with default options for the platform.
engine = Engine()

# Define an instrument
engine.defInstr('''
  instr synth
    ; pfields of the instrument
    kmidinote = p4
    kamp = p5
    kcutoff = p6
    kdetune = p7

    kfreq = mtof:k(kmidinote)
    ; A filtered sawtooth
    asig  = vco2:a(kamp*0.7, kfreq)
    asig += vco2.a(kamp*0.7, kfreq + kdetune)
    asig = moogladder2(asig, kcutoff, 0.9)
    ; Attack / Release
    aenv = linsegr:a(0, 0.01, 1, 0.2, 0)
    asig *= aenv
    outs asig, asig
  endin
''')

# Start a synth with indefinite duration. This returns the eventid (p1)
# of the running instrument, which can be used to further control it
event = engine.sched("synth", args=[48, 0.2, 3000, 4])

# Change midinote. setp means: set p-field. This sets p4 (kmidinote) to 50
engine.setp(event, 4, 50)

# Modify cutoff
engine.setp(event, 6, 1000, delay=4)

# Stop the synth
engine.unsched(event)

Session - high level interface

Each engine can have an associated Session. A Session provides a higher level interface, allowing to:

  • Define instrument templates (an Instr), which can be instantiated at any order of evaluation, allowing to implement processing chains of any complexity

  • An Instr can have named parameters which can be used to control the event.

  • A Session provides a series of built-in Instr’s to perform some common tasks, like playing samples from memory or from disk, perform audio analysis, etc.

from csoundengine import *

# Create an Engine and a corresponding Session using default options
session = Engine().session()

# create a master audio channel
masterbus = session.newBus()

# define instruments
session.defInstr("synth", r'''
  |ibus, kmidi=60, kamp=0.1, ktransp=0, ifade=0.5|
  ; a simple sawtooth
  asig vco2 kamp, mtof:k(kmidi+ktransp)
  asig *= linsegr:a(0, ifade, 1, ifade, 0)
  ; output is routed to a bus
  busout(ibus, asig)
''')

session.defInstr("filter", r'''
  |ibus, imasterbus, kcutoff=1000, kresonance=0.9|
  asig = busin(ibus)
  asig = moogladder2(asig, kcutoff, kresonance)
  busmix(imasterbus, asig)
''')

session.defInstr("master", r'''
  imasterbus = p4
  asig = busin(imasterbus)
  asig compress2 asig, asig, -120, -40, -12, 3, 0.1, 0.01, 0.05
  outch 1, asig
''')

# Start a master instance at the end of the evaluation chain
master = session.sched("master", imasterbus=masterbus.busnum, priority=10)

# Launch some notes
for i, midinote in enumerate(range(60, 72, 2)):
    # for each synth, we create a bus to plug it to an effect, in this case a filter
    bus = session.newBus()

    # start time for synth and effect
    start = i * 1

    # Schedule a synth
    synth = session.sched("synth", delay=start, dur=5, kmidi=midinote, ibus=bus.busnum)

    # Automate pitch transposition so that it descends 2 semitones over the
    # duration of the event
    synth.automatep('ktransp', [0, 0, dur, -2], delay=start)

    # Schedule the filter for this synth, with a priority higher than the
    # synth, so that it is evaluated later in the chain
    filt = session.sched("filter",
                         delay=start,
                         dur=synth.dur,
                         priority=synth.priority+1,
                         kcutoff=2000,
                         kresonance=0.92,
                         ibus=bus.busnum,
                         imasterbus=masterbus.busnum,
                         whenfinished=lambda p1, bus=bus: bus.free())

    # Automate the cutoff freq. of the filter
    filt.automatep('kcutoff', [0, 2000, dur*0.8, 500, dur, 6000], delay=start)

Installation

https://csoundengine.readthedocs.io/en/latest/Installation.html

Dependencies

With all external dependencies in place, installation is simple:

pip install csoundengine

Documentation

https://csoundengine.readthedocs.io

Project details


Release history Release notifications | RSS feed

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

csoundengine-0.1.1.tar.gz (72.9 kB view hashes)

Uploaded Source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page