Python输出声音

Python输出声⾳
常见的波形图
以三⾓波为例，不同的频率产⽣不同声⾳
⽹上可以查到C4调，D4调，E4调的频率
C4D4E4F4G4A4B4
261.63293.66329.63349.23392.00440.00493.88
常⽤的⾳频采样频率有8kHz、11.025kHz、22.05kHz、16kHz、37.8kHz、44.1kHz、48kHz等from wave import open
from struct import Struct
from math import floor
sampler_rate=11025
"""对连续三⾓波函数进⾏离散取样"""
def tri(frequency, amplitude=0.3):
"""a continuous triangle wave"""
wave_length = sampler_rate // frequency
# range from -0.3 to 0.3
def sampler(t):
saw_wave = t / wave_length - floor(t / wave_length + 0.5)
tri_wave = 2 * abs(2 * saw_wave) - 1
return amplitude * tri_wave
return sampler
def encode(x):
"""Encode float x between -1 and 1 as two bytes.
(See https:///3/library/struct.html)
"""
i = int(16384 * x)
return Struct('h').pack(i)
def play(sampler, name="song.wav", seconds=2):
"""
当输出持续2s的声⾳⽂件时，需要采样 2*sampler_rate=22250次
"""
out = open(name, "wb")
out.setnchannels(1)
out.setsampwidth(2)
out.setframerate(sample_rate)
t = 0
while t < seconds * sample_rate:
sample = sampler(t)
out.writeframes(encode(sample))
t = t + 1
out.close()
play(tri(e_freq))
这样输出的⾳频很难听，还需要对波形做⼀些调整。

def note(f, start, end, fade=.01):
"""Play f for a fixed duration."""
def sampler(t):
seconds = t / sampler_rate
if seconds < start:
return 0
elif seconds > end:
return 0
elif seconds < start + fade:
return (seconds - start) / fade * f(t)
elif seconds > end - fade:
return (end - seconds) / fade * f(t)
else:
return f(t)
return sampler
play(note(tri(e_freq), 1, 1.5)) #在(1,1.5)之间播放E4调
输出⼀段马⾥奥前奏
def both(f, g):
return lambda t: f(t) + g(t)
def mario(c, e, g, low_g):
z = 0
song = note(e, z, z + 1 / 8)
z += 1 / 8
song = both(song, note(e, z, z + 1 / 8))
z += 1 / 4
song = both(song, note(e, z, z + 1 / 8))
z += 1 / 4
song = both(song, note(c, z, z + 1 / 8))
z += 1 / 8
song = both(song, note(e, z, z + 1 / 8))
z += 1 / 4
song = both(song, note(g, z, z + 1 / 4))
z += 1 / 2
song = both(song, note(low_g, z, z + 1 / 4)) return song
def mario_at(octave):
c = tri(octave * c_freq)
e = tri(octave * e_freq)
g = tri(octave * g_freq)
low_g = tri(octave * g_freq / 2)
return mario(c, e, g, low_g)
play(both(mario_at(1), mario_at(1 / 2)))。