如何连续改变正弦声音的频率? [英] How to change continuously the frequency of a sinusoidal sound?
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问题描述
我正在使用Pygame
在窗口中渲染Sprite,我想播放正弦声音,其频率取决于该Sprite的y
位置.我不希望信号相位不连续.实现此目标的最佳方法是什么?
I am using Pygame
to render a Sprite in a window and I want to play a sinusoidal sound which frequency depends on the y
position of that Sprite. I don't want discontinuities in the phase of the signal. What's the best way to achieve this?
推荐答案
我想出了这个解决方案.
将freq
更改为newfreq
,然后更改相位,如下所示:newphase = 2*np.pi*t*(freq-newfreq)+phase
I came up with this solution.
Change the freq
to newfreq
and then change the phase like this: newphase = 2*np.pi*t*(freq-newfreq)+phase
import pyaudio
import numpy as np
from time import time
CHANNELS = 2
RATE = 44100
TT = time()
freq = 100
newfreq = 100
phase = 0
def callback(in_data, frame_count, time_info, status):
global TT,phase,freq,newfreq
if newfreq != freq:
phase = 2*np.pi*TT*(freq-newfreq)+phase
freq=newfreq
left = (np.sin(phase+2*np.pi*freq*(TT+np.arange(frame_count)/float(RATE))))
data = np.zeros((left.shape[0]*2,),np.float32)
data[::2] = left
data[1::2] = left
TT+=frame_count/float(RATE)
return (data, pyaudio.paContinue)
p = pyaudio.PyAudio()
stream = p.open(format=pyaudio.paFloat32,
channels=CHANNELS,
rate=RATE,
output=True,
stream_callback=callback)
stream.start_stream()
start = time()
try:
while 1:
now = time()
if now-start>1/24.:
newfreq=200+np.sin(2*np.pi*1/20.*now)*100 #update the frequency This will depend on y on the future
print newfreq
start=now
finally:
stream.stop_stream()
stream.close()
p.terminate()
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