Hello all,
I had a look in the mailing list archives for FFT and Fourier, and couldn't
find anything that looked relevant.
The following code has a surprising result: it outputs sound.wav twice. I'd
expect some random sounding noise the second time. There's nothing in the
documentation for pygame.sndarray about make_sound understanding FFTs.
How/why does it work this way? I've tried this with a few different sounds
in case it was a property of the one sound.
I'm interested in playing with real number Fourier coefficients to
manipulate and produce sounds. However, I'm not sure what pygame is doing
exactly, which makes it harder to work on. Perhaps it's something about FFTs
I don't understand? Can anyone explain? I've just noticed that the second
playback is only on one side, whilst the first is on both. Curiouser and
curiouser...
Russell
import pygame
import pygame.mixer as pm
import pygame.sndarray as sa
import numpy as np
import time
pygame.init()
pm.init(frequency=44100, size=16, channels=1, buffer=4096)
sample=sa.array(pm.Sound("sound.wav"))
fft=np.fft.rfft(np.array(sample,dtype=np.int32))
ch=None
while not ch:
ch=pm.find_channel()
time.sleep(1)
s=sa.make_sound(np.array(np.fft.irfft(fft), dtype=np.int16))
ch.queue(s)
time.sleep(len(sample)*2/44100.0)
s=sa.make_sound(np.array(fft, dtype=np.int16))
ch.queue(s)
time.sleep(len(sample)*2/44100.0)
