On Thu, 17 Jun 2010 23:44:28 +0400
Louigi Verona <louigi.ver...@gmail.com> wrote:
> Hello Simon!
> I am interested - how do you achieve phasing on Linux? Using what tools?
>
> --
> Louigi Verona
> http://www.louigiverona.ru
>
Check this out.. you will need python and numpy.
Simon.
#!/usr/bin/env python
import sys
from math import sqrt
import wave
import numpy
scalar = numpy.float32
SAMPLERATE = 44100
def read_wave(filename):
w = wave.open(filename)
chunks = []
count = 0
while 1:
chunk = w.readframes(4096)
if not chunk:
break
count += len(chunk)
chunks.append(chunk)
a = numpy.empty(count, numpy.float32)
i = 0
for chunk in chunks:
b = numpy.fromstring(chunk, numpy.int16)
n = len(b)
a[i:i+n] = b
i += n
assert i == count/2
x0, x1 = a.min(), a.max()
assert x0<x1
a = a / (x1-x0)
return a
def normalize(a, volume=1.):
print "peak-to-peak: %.2f" % (a.max()-a.min())
assert 0. <= volume <= 1.
if a.max() - a.min() > 1e-8:
#centre = (a.max() + a.min()) / 2
#a -= centre
a *= float(volume) * 32767 / (a.max() - a.min())
else:
print " *** quiet array"
return a.astype(numpy.int16)
def write_wave(filename, a, samplerate=SAMPLERATE):
assert len(a.shape)==1 or a.shape[1] in (1, 2), "odd shape = %r"%(a.shape,)
channels = 1 if len(a.shape)==1 else a.shape[1]
print "write_wave", filename, 'channels=', channels
a = normalize(a)
f = wave.open(filename, 'w')
f.setnchannels(channels)
f.setsampwidth(2)
f.setframerate(samplerate)
f.writeframesraw(a.tostring())
f.close()
_window_cache = {}
def window(a, d_idx=None, attack=100, decay=100):
#print "window", len(a), d_idx, attack, decay
if d_idx is None:
d_idx = len(a)
key = (d_idx, attack, decay)
w = _window_cache.get(key)
if w is None:
w = numpy.empty(d_idx, dtype=scalar)
w[:] = 1.
for idx in range(attack):
w[int(idx)] = 1.*idx/float(attack)
for idx in range(decay):
w[int(d_idx - idx-1)] = 1.*idx/float(decay) # ramp up
_window_cache[key] = w
a = a[0 : d_idx]
a = a*w
return a
def paint(a, b, idx0, idx1=None):
if idx1 is None:
idx1 = len(b)
idx0 = int(idx0)
idx1 = int(idx1)
adx0, adx1 = idx0, idx0+idx1
bdx0, bdx1 = 0, idx1
try:
a[adx0 : adx1] += b[bdx0 : bdx1]
except ValueError:
print "paint: ValueError"
pass
def main(source, target, stacks=10, dt=0.1, cycles=30):
a = read_wave(source)
N = len(a) * cycles
A = numpy.zeros((N,), scalar) # use (N, 2) for stereo output
dn = dt * SAMPLERATE
bs = [a[:len(a) - dn*i] for i in range(stacks)]
for b in bs:
idx = 0
while idx + len(b) < len(A):
b = window(b)
paint(A[:], b, idx)
idx += len(b)
#a = A[len(a):] # skip the first cycle...
A[:len(a)] /= sqrt(cycles) # attenuate the first cycle...
write_wave(target, A)
if __name__ == "__main__":
if not sys.argv[1:]:
print "USAGE:\n\tphaser.py source.wav target.wav\n"
else:
source = sys.argv[1]
target = sys.argv[2]
main(source, target)
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