ref: c4c51309beb1476e54845bdca78fe46f64449c7c
dir: /python/demos/demo_sink_create_woodblock.py/
#! /usr/bin/env python import sys from math import pi, e from aubio import sink from numpy import arange, resize, 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 = 'float32') sinetable = 0.7 * sin(twopi * sinetable/tablelen) sinetone = zeros((duration,), dtype = 'float32') # 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 = 'float32') 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)