ref: b4445fb25f9c4bc904a4782f9ad8a4fa1afd2b79
dir: /python/demos/demo_sink_create_woodblock.py/
#! /usr/bin/env python
import sys
from math import pi, e
from aubio import sink, float_type
from numpy import arange, sin, exp, zeros
if len(sys.argv) < 2:
print('usage: %s <outputfile> [samplerate]' % sys.argv[0])
sys.exit(1)
samplerate = 44100 # samplerate in Hz
if len( sys.argv ) > 2: samplerate = int(sys.argv[2])
pitch = 2200 # in Hz
blocksize = 256 # in samples
duration = 0.02 # in seconds
twopi = pi * 2.
duration = int ( samplerate * duration ) # convert to samples
attack = int (samplerate * .001 )
decay = .5
period = float(samplerate) / pitch
# create a sine lookup table
tablelen = 1000
sinetable = arange(tablelen + 1, dtype = float_type)
sinetable = 0.7 * sin(twopi * sinetable/tablelen)
sinetone = zeros((duration,), dtype = float_type)
# compute sinetone at floating point period
for i in range(duration):
x = int((i % period) / float(period) * tablelen)
idx = int(x)
frac = x - idx
a = sinetable[idx]
b = sinetable[idx + 1]
sinetone[i] = a + frac * (b -a)
# apply some envelope
float_ramp = arange(duration, dtype = float_type)
sinetone *= exp( - e * float_ramp / duration / decay)
sinetone[:attack] *= exp( e * ( float_ramp[:attack] / attack - 1 ) )
if 1:
import matplotlib.pyplot as plt
plt.plot(sinetone)
plt.show()
my_sink = sink(sys.argv[1], samplerate)
total_frames = 0
while total_frames + blocksize < duration:
my_sink(sinetone[total_frames:total_frames+blocksize], blocksize)
total_frames += blocksize
my_sink(sinetone[total_frames:duration], duration - total_frames)