python - 使用 numpy 和 scipy 生成波形文件后波形之间的间隙

Question

我使用 python 3.7、numpy 和 scipy 编写了一个程序，该程序使用 pi 的数字生成波形，并将它们拼接在一起以制作“歌曲”。我唯一的问题是每个音符之间都有间隙。

我尝试过使用数学函数让每个音符的波浪淡出，我尝试让音符重叠一点(运气不太好)，还有一些更疯狂的事情没有做任何事情...

import numpy as np
from scipy.io.wavfile import write

pi = "3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848"
piarray = list(pi)
piarray.remove(".")

print(piarray)

# Samples per second
sps = 44100

# Frequency / pitch of the sine wave
freq_hz = 440.0

# Duration
duration_s = 0.2

each_sample_number = np.arange(duration_s * sps)

for i in range(len(piarray)):
    if(piarray[i] == "0"):
        freq_hz = 277.18
    elif(piarray[i] == "1"):
        freq_hz = 311.13
    elif(piarray[i] == "2"):
        freq_hz = 369.99
    elif(piarray[i] == "3"):
        freq_hz = 415.30
    elif(piarray[i] == "4"):
        freq_hz = 466.16
    elif(piarray[i] == "5"):
        freq_hz = 554.37
    elif(piarray[i] == "6"):
        freq_hz = 622.25
    elif(piarray[i] == "7"):
        freq_hz = 739.99
    elif(piarray[i] == "8"):
        freq_hz = 830.61
    else:
        freq_hz = 932.33

    waveform = np.sin(2 * np.pi * each_sample_number * freq_hz / sps)*0.3
    #The line above and below this one make an individual note.
    waveform_integers = np.int16(waveform * 32767)

    if(i == 0):
        waveformc = waveform_integers
        print(waveformc)
    else:
        waveformc = np.append(waveformc, waveform_integers, axis=None)

write('song.wav', sps, waveformc)
print("DONE")

我已经尝试寻找解决这个特定问题的方法，但我没有在任何地方找到任何相关的东西。我只是希望波形文件在每个音符之间没有间隙，但是有。感谢您能给我的任何帮助!

Answer 1

您的波形之间没有任何间隙。您可以从 Reaper 的结果 View 中看到您有连续的声音:

每次开始一个新音符时，您的波形都会出现不连续性。每次音符更改时，都会听到咔哒声或爆裂声。由于每个音符的波形都是根据底层数据结构计算的，因此它们都将在 0s 处有一个零交叉点，然后从那里快速彼此脱离一个相位。

要解决此问题，您可以尝试适本地逐渐淡入/淡出每种声音，或者确保跟踪波形的相位并在音符变化时保持一致。

对于衰减函数，您需要符合 (frames - each_sample_number)/frames)**n 的内容，以便它在最后达到零。您可以尝试使用此函数，看看它如何影响声音的持续时间和音符之间的感知削波。

import numpy as np
from scipy.io.wavfile import write

pi = "3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848"
piarray = list(pi)
piarray.remove(".")

print(piarray)

# Samples per second
sps = 44100

# Frequency / pitch of the sine wave
freq_hz = 440.0

# Duration
duration_s = 0.2
frames = duration_s * sps # counting how many frames for a note
each_sample_number = np.arange(duration_s * sps)



for i in range(len(piarray)):
    if(piarray[i] == "0"):
        freq_hz = 277.18
    elif(piarray[i] == "1"):
        freq_hz = 311.13
    elif(piarray[i] == "2"):
        freq_hz = 369.99
    elif(piarray[i] == "3"):
        freq_hz = 415.30
    elif(piarray[i] == "4"):
        freq_hz = 466.16
    elif(piarray[i] == "5"):
        freq_hz = 554.37
    elif(piarray[i] == "6"):
        freq_hz = 622.25
    elif(piarray[i] == "7"):
        freq_hz = 739.99
    elif(piarray[i] == "8"):
        freq_hz = 830.61
    else:
        freq_hz = 932.33

    # added fall off feature
    waveform = (((frames - each_sample_number) / frames)**0.5) * np.sin(
                        np.pi+ 2 * np.pi * each_sample_number * freq_hz / sps)*0.3

    #The line above and below this one make an individual note.
    waveform_integers = np.int16(waveform * 32767)

    if(i == 0):
        waveformc = waveform_integers
        print(waveformc)
    else:
        waveformc = np.append(waveformc, waveform_integers, axis=None)

write('song.wav', sps, waveformc)
print("DONE")

可以在波形上看到当前设置的结果: