Using Python as the RTcmix Command-Language Interface

Building RTcmix with Python Support

[note: click here for documentation on setting up RTcmix-python on Mac OSX.]

Very similar to the Perl front-end procedure for RTcmix, you will need to edit the "makefile.conf" file prior to compiling RTcmix (see the installation guide for information about this), you can enable Python support by uncommenting the PYTHON_SUPPORT = TRUE line and setting up the PYTHON = python assignment appropriately for your computer:

# Uncomment this to enable use of the Python front end to RTcmix.
#PYTHON_SUPPORT = TRUE
# Say which python to use: just "python" if you only have one; otherwise,
# give full path name of python to use, e.g., /usr/local/bin/python.
PYTHON = python

Once you do this and (re-)compile RTcmix, you're set to go with a Python front-end. As with Perl, this can be used in place of the default scorefile language Minc. You will need to use the PCMIX command instead of CMIX

Using Python/RTcmix

This works a lot like the Perl RTcmix, but the following note is in the "RTcmix/Python" directory:

-  Namespace clashes with Python builtin functions:

      abs
      input
      max
      open
      pow
      round

   The cmix ones seem to have priority (because they were loaded
   most recently?).
  
- The ability to kill the job and still see peak stats doesn't work,
  though it does work in PCMIX.  Python is nuking our signal handler
  (sigint_handler in main.C) somehow?  Strange, because supposedly
  the interpreter is destroyed before we start playing score, by
  parse_score in Minc/parse_with_python.c.  The comments in parse_score
  imply that this used to work with Python 1.x.

- To build python on OS X, see http://www.zope.org/Members/jens/docs/zope_osx

Sample Scorefiles

Python script showing the RTcmix ability to chain several instruments together:

# Quick translation of sample_scos_3.0/LONGCHAIN_1.sco to Python, for testing.

# This score makes a wavetable synth riff and feeds it through 3 effects
# in series: flange -> delay -> reverb

from rtcmix import *

print_off()
rtsetparams(44100, 2)
load("WAVETABLE")
load("FLANGE")
load("JDELAY")
load("REVERBIT")

bus_config("WAVETABLE", "aux 0-1 out")
bus_config("FLANGE", "aux 0-1 in", "aux 10-11 out")
bus_config("JDELAY", "aux 10-11 in", "aux 4-5 out")
bus_config("REVERBIT", "aux 4-5 in", "out 0-1")

totdur = 30
masteramp = 1.0
atk = 2; dcy = 4

notes = [5.00, 5.001, 5.02, 5.03, 5.05, 5.07, 5.069, 5.10, 6.00]
numnotes = len(notes)

transposition = 2.00    # try 7.00 also, for some cool aliasing...
srand(2)


# ---------------------------------------------------------------- synth ---
notedur = .10
incr = notedur + .015

maxampdb = 92
minampdb = 75
ampdiff = maxampdb - minampdb

control_rate(20000)         # need high control rate for short synth notes
setline(0,0, 1,1, 20,0)
makegen(2, 10, 10000, 1, .9, .7, .5, .3, .2, .1, .05, .02)

st = 0
while st < totdur:
   slot = int(random() * numnotes * .999999)
   pitch = pchoct(octpch(notes[slot]) + octpch(transposition))
   amp = ampdb(minampdb + (ampdiff * random()))
   pctleft = random()
   WAVETABLE(st, notedur, amp, pitch, pctleft)
   st = st + incr


# for the rest
control_rate(500)
amp = masteramp

# --------------------------------------------------------------- flange ---
resonance = 0.3
lowpitch = 5.00
moddepth = 90
modspeed = 0.08
wetdrymix = 0.5
flangetype = 0

gensize = 100000
makegen(2,10,gensize, 1)

maxdelay = 1.0 / cpspch(lowpitch)

setline(0,1,1,1)

st = 0; insk = 0; inchan = 0; pctleft = 1
FLANGE(st, insk, totdur, amp, resonance, maxdelay, moddepth,
       modspeed, wetdrymix, flangetype, inchan, pctleft)

lowpitch = lowpitch + .07
maxdelay = 1.0 / cpspch(lowpitch)

makegen(2,9,gensize, 1,1,-180)

st = 0; insk = 0; inchan = 1; pctleft = 0
FLANGE(st, insk, totdur, amp, resonance, maxdelay, moddepth,
       modspeed, wetdrymix, flangetype, inchan, pctleft)


# ---------------------------------------------------------------- delay ---
deltime = notedur * 2.2
regen = 0.70
wetdry = 0.12
cutoff = 0
ringdur = 2.0

setline(0,0, atk,1, totdur-dcy,1, totdur,0)

st = 0; insk = 0; inchan = 0; pctleft = 1
JDELAY(st, insk, totdur, amp, deltime, regen, ringdur, cutoff,
       wetdry, inchan, pctleft)
st = 0.02; inchan = 1; pctleft = 0
JDELAY(st, insk, totdur, amp, deltime, regen, ringdur, cutoff,
       wetdry, inchan, pctleft)


# --------------------------------------------------------------- reverb ---
revtime = 1.0
revpct = .3
rtchandel = .05
cf = 0

setline(0,1, 1,1)

st = 0; insk = 0
REVERBIT(st, insk, totdur+ringdur, amp, revtime, revpct, rtchandel, cf)



# john gibson, 13-feb-01