python生成特定频率、特定音量的正弦波wav文件（升级版）

第一版：https://mp.csdn.net/postedit/102664748 

import wave
import numpy as np
import struct
import matplotlib.pyplot as plt
import math
#from compiler.ast import flatten

#db = 0
print ("math.pow(10, -12/20) : ", math.pow(10, -12/20)) # 0.251188643150958
print ("math.pow(10, -6/20) : ", math.pow(10, -6/20)) #0.5011872336272722
print ("math.pow(10, -3/20) : ", math.pow(10, -3/20)) #0.7079457843841379
print ("math.pow(10, -1/20) : ", math.pow(10, -1/20)) #0.8912509381337456
print ("math.pow(10, 0/20) : ", math.pow(10, 0/20)) #1.0
print ("math.pow(10, 1/20) : ", math.pow(10, 1/20)) #1.1220184543019633
print ('math.pow(10, 3/20) : ', math.pow(10, 3/20)) #1.4125375446227544
print ('math.pow(10, 6/20) : ', math.pow(10, 6/20)) #1.9952623149688795
print ('math.pow(10, 9/20) : ', math.pow(10, 9/20)) #2.8183829312644537
print ('math.pow(10, 12/20) : ', math.pow(10, 12/20)) #3.9810717055349722
# volume x_db
db_v = -3
db = math.pow(10, -3/20)
# sample/every second
framerate = 44100
# channel_num
channel_num = 2
# bytes needed every sample
sample_width = 2
bits_width = sample_width*8
# seconds, long of data
duration = 1
# frequeny of sinewave
sinewav_frequency_l = 1000
sinewav_frequency_r = 2000
# max value of samples, depends on bits_width
max_val = 2**(bits_width-1) - 1
print ('max_val : ', max_val)
#volume = 32767*db #0x7FFF=32767
volume = max_val*db #2**(bits_width-1) - 1
#多个声道生成波形数据
x = np.linspace(0, duration, num=duration*framerate)
y_l = np.sin(2 * np.pi * sinewav_frequency_l * x) * volume
y_r = np.sin(2 * np.pi * sinewav_frequency_r * x) * volume
# 将多个声道的波形数据转换成数组
y = zip(y_l,y_r)
print("zip y", y)
y = list(y)
print("list y",y)
y = np.array(y,dtype=np.int)
print("array y",y)
y = y.reshape(-1)
print("reshap array y",y)

# 最终生成的一维数组
sine_wave = y
# wav file_name
file_name = "sine_"+str(framerate)+"_"+str(channel_num)+"ch_"+str(db_v)+"db_l"+str(sinewav_frequency_l)+"_r"+str(sinewav_frequency_r)+"_"+str(duration)+"s.wav"
print ('file_name: ', file_name)
#open wav file
wf = wave.open(file_name, 'wb')#wf = wave.open("sine.wav", 'wb')
wf.setnchannels(channel_num)
wf.setframerate(framerate)
wf.setsampwidth(sample_width)
for i in sine_wave:
    data = struct.pack('<h', int(i))
    wf.writeframesraw(data)
wf.close()