Question

我刚刚开始学习isochronic tones，并开始编写基本的Python脚本以生成相同的内容。以下是我为执行以下操作而编写的脚本：

生成拍频的梯形波

用拍频的梯形波调制基频的正弦波

#!/usr/bin/env python
# encoding: utf-8

"""
Small program for creating Isochronic Tones of desired base frequency, beat frequency and ramp frequencies
"""

import math
import wave
import struct
import array
import sys

def make_isochronic_wave(beat_freq, beat_ramp_percent, beat_sampl_rate, beat_time, base_freq, amplitude):

#
# The time for which the trapezoidal beat frequency wave is present in the entire cycle
#
up_time = 1 / beat_freq

#
# Gap between consequtive trapezoidal beats
#
gap_percent = up_time * 0.15

#
# To accomodate gaps
#
up_time = up_time * 0.85

#
# Total number of samples
#
data_size = beat_sampl_rate * beat_time

#
# No. of gaps per sec = No. of beats per sec
#
no_of_gaps = beat_freq

#
# Samples per gap = percentage of total time allocated for gaps * No. of samples per sec
#
sampls_per_gap = gap_percent * beat_sampl_rate

#
# Total number of samples in all the gaps
#
gap_sampls = no_of_gaps * sampls_per_gap

#
# Change the beat sample rate to accomodate gaps
#
beat_sampl_rate = beat_sampl_rate - gap_sampls

#
# nsps = Number of Samples Per Second
#
# NOTE: Please see the image at: 
#
beat_nsps_defined = beat_sampl_rate * up_time

beat_nsps_inc = beat_nsps_defined * beat_ramp_percent

beat_nsps_dec = beat_nsps_defined * beat_ramp_percent

beat_nsps_stable = beat_nsps_defined - (beat_nsps_inc + beat_nsps_dec)

beat_nsps_undefined = beat_sampl_rate - beat_nsps_defined

#
# Trapezoidal values
#
values = []

#
# Trapezoidal * sine == Isochronic values
#
isoch_values = []

#
# Samples constructed
#
sampls_const = 0

#
# Iterate till all the samples in data_size are constructed
#
while sampls_const < data_size:
    prev_sampl_value_inc = 0.0
    prev_sampl_value_dec = 1.0
    #
    # Construct one trapezoidal beat wave (remember this is not the entire sample)
    #
    for sampl_itr in range(0, int(beat_sampl_rate)):
        if sampl_itr < beat_nsps_inc:
            value = prev_sampl_value_inc + (1 / beat_nsps_inc)
            prev_sampl_value_inc = value
            values.append(value)
        if sampl_itr > beat_nsps_inc:
            if sampl_itr < (beat_nsps_inc + beat_nsps_stable):
                value = 1
                values.append(value)
            elif (sampl_itr > (beat_nsps_inc + beat_nsps_stable)) and (sampl_itr < (beat_nsps_inc + beat_nsps_stable + beat_nsps_dec)):
                value = prev_sampl_value_dec - (1 / beat_nsps_dec)
                prev_sampl_value_dec = value
                values.append(value)

    #
    # Add the gap cycles
    #
    for gap_iter in range(0, int(sampls_per_gap)):
        values.append(0)

    #
    # Increment the number of samples constructed to reflect the values
    #
    sampls_const = sampls_const + beat_nsps_defined + gap_sampls

#
# Open the wave file
#
wav_file = wave.open("beat_wave_%s_%s.wav" % (base_freq, beat_freq), "w")

#
# Define parameters
#
nchannels = 2
sampwidth = 2
framerate = beat_sampl_rate
nframes = data_size
comptype = "NONE"
compname = "not compressed"

wav_file.setparams((nchannels, sampwidth, framerate, nframes, comptype, compname))

#
# Calculate isochronic wave point values
#
value_iter = 0

for value in values:
    isoch_value = value * math.sin(2 * math.pi * base_freq * (value_iter / beat_sampl_rate))
    value_iter = value_iter + 1
    isoch_values.append(isoch_value)

#
# Create the wave file (in .wav format)
#
for value in isoch_values:
    data = array.array('h')
    data.append(int(value * amplitude / 2)) # left channel
    data.append(int(value * amplitude / 2)) # right channel

    wav_file.writeframes(data.tostring())


wav_file.close()

try:
    base_freq = int(sys.argv[1], 10)
    beat_freq = int(sys.argv[2], 10)
    sample_rate = int(sys.argv[3], 10)
    output_time = int(sys.argv[4], 10)
    ramp_percent = float(sys.argv[5])
    amplitude = float(sys.argv[6])

    make_isochronic_wave(beat_freq, ramp_percent, sample_rate, output_time, base_freq, amplitude)
except:
    msg = """
<program> <base freqency> <beat frequency> <sample rate> <output time> <ramp percent> <amplitude>
"""
    print (msg)

上面的代码运行良好，并且得到了以下格式的波形：

以上格式类似于使用IsoMod插件使用audacity生成的格式。但是，我想产生一种拍频，该拍频的拍频会降低。为此，我增强了上面的脚本，以每秒一次的循环调用梯形波的产生。但是，将wav文件的参数设置为多次写入（由于跨斜坡的beat_freq的变化而导致data_size的变化），我得到了以下错误

G:\>python gen_isochronic_tones.py 70 10 5 11025 5 0.15 8000
gen_isochronic_tones.py:195: DeprecationWarning: tostring() is deprecated. Use tobytes() instead.
  make_isochronic_wave(beat_freq_start, beat_freq_end, ramp_percent, sample_rate, output_time, base_freq, amplitude)
Traceback (most recent call last):
  File "gen_isochronic_tones.py", line 195, in <module>
    make_isochronic_wave(beat_freq_start, beat_freq_end, ramp_percent, sample_rate, output_time, base_freq, amplitude)
  File "gen_isochronic_tones.py", line 156, in make_isochronic_wave
    wav_file.setparams((nchannels, sampwidth, framerate, data_size, comptype, compname))
  File "G:\Python37-32\lib\wave.py", line 399, in setparams
    raise Error('cannot change parameters after starting to write')
wave.Error: cannot change parameters after starting to write

像wave模块一样，允许参数（即上面的data_size）仅更改一次。知道如何使它能够更改data_size吗？

python中的等时音调的拍频变化

0 个答案: