libcsound

Python bindings for Csound (fork of ctcsound)

These bindings can be used with any version of csound >= 6.18. Csound 7 is explicitely supported and is the recommended version.

Installation

Csound

Csound does not need to be installed manually: when it cannot be found, libcsound installs csound 7 automatically on import, on Linux, macOS and Windows (unless LIBCSOUND_INSTALL is set to 0 or false). On macOS the install runs under sudo, so it needs either an interactive terminal or passwordless sudo (as on CI runners); on Windows it is machine-wide and needs Administrator rights, so an interactive or already-elevated session is required.

To install csound manually instead, use the official installers. See https://github.com/csound/csound/releases

In Linux / macOS:

curl -fsSL https://csound-plugins.github.io/getcsound.sh | bash

In Windows:

irm https://csound-plugins.github.io/getcsound.ps1 | iex

This installs the latest version of csound 7.

libcsound

pip install libcsound

Environment variables

The csound shared library is located and loaded when libcsound is imported, so these variables must be set before importing it.

• LIBCSOUNDPATH: absolute path to the csound shared library to load. When set, no other search is performed. If unset, the library is searched in the system path.
• LIBCSOUND_INSTALL: set to 0 or false to disable the automatic installation of csound when it cannot be found.

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Quick Start

Rendering in real-time using a render thread

import libcsound
csound = libcsound.Csound()
csound.setOption('-odac')
csound.compileOrc(r'''

sr = 44100   ; Modify to fit your system
ksmps = 64
nchnls = 2
0dbfs = 1

instr 1
  kchan init -1
  kchan = (kchan + metro:k(1)) % nchnls
  if changed:k(kchan) == 1 then
    println "Channel: %d", kchan + 1
  endif
  asig = pinker() * 0.2
  outch kchan + 1, asig
endin

''')
csound.start()
thread = csound.performanceThread()
thread.play()
# Schedule an instance of instr 1 for 10 seconds
thread.scoreEvent(0, "i", [1, 0, 10])
input("Press any key to stop...\n")
thread.stop()

Render offline

import libcsound
csound = libcsound.Csound()
csound.setOption('-ooutfile.wav')
csound.compileOrc(r'''

sr = 44100
ksmps = 64
nchnls = 2
0dbfs = 1

instr 1
  kchan init -1
  kchan = (kchan + metro:k(1)) % nchnls
  if changed:k(kchan) == 1 then
    println "Channel: %d", kchan + 1
  endif
  asig = pinker() * 0.2
  outch kchan + 1, asig
endin

''')
csound.start()
csound.scoreEvent("i", [1, 0, 10])
csound.setEndMarker(10)
# Perform until the end of the score
while not csound.performKsmps():
    pass

Documentation

https://libcsound.readthedocs.io/en/latest/