音符模拟发生

sonic_freq.py

#!/usr/bin/python 
# coding: UTF-8
import time
import numpy as np
from numpy.fft import fft, ifft
from numpy.random import random_sample
from alsaaudio import PCM, PCM_NONBLOCK, PCM_FORMAT_FLOAT_LE

C_freq = np.float128(440)
magic = 2 ** (1/12.)
init_freq = C_freq * (magic ** -(4 * 12 + 9))  #C0
note = ['C', 'C♯/D♭', 'D', 'D♯/E♭', 'E', 'F', 'F♯/G♭', 'G', 'G♯/A♭', 'A', 'A♯/B♭', 'B']
octave = range(11)
srate = 44100
dur = 44100


pcm = PCM()#mode=PCM_NONBLOCK)
pcm.setrate(srate)
pcm.setformat(PCM_FORMAT_FLOAT_LE)
pcm.setchannels(1)
pcm.setperiodsize(dur)

def sine_wave(x, freq=100):
    sample = np.arange(x*dur, (x+1)*dur, dtype=np.float32)
    sample *= np.pi * 2 / srate
    sample *= freq
    return np.sin(sample)

for i in xrange(len(octave)):
    for j in xrange(len(note)):
        x = i * len(octave)  + j
        sample = sine_wave(x, init_freq)
        pcm.write(sample.tostring())
        print '%s\'th beep with octave:%s, note:%s, freq:%s' % \
        (x + 1,octave[i],note[j],init_freq)
        time.sleep( float(srate/dur) )
        init_freq *= magic
pcm.close()