def invpostaud(y, fmax, fb_type='bark', broaden=0):
"""
invert the effects of postaud (loudness equalization and cube
- root compression)
- y = postaud output
- x = reconstructed critical band filters
- rows = critical bands
- cols = frames
"""
nbands, nframes = y.shape
if fb_type == 'bark':
bandcfhz = bark2hz(np.linspace(0, hz2bark(fmax), nbands))
elif fb_type == 'mel':
bandcfhz = mel2hz(np.linspace(0, hz2mel(fmax), nbands))
elif fb_type == 'htkmel' or fb_type == 'fcmel':
bandcfhz = mel2hz(np.linspace(0, hz2mel(fmax, htk=True), nbands),
htk=True)
bandcfhz = bandcfhz[broaden:(nbands - broaden)]
fsq = bandcfhz**2
ftmp = fsq + 1.6e5
eql = np.multiply((fsq / ftmp)**2, (fsq + 1.44e6) / (fsq + 9.61e6))
x = y**(1 / 0.33)
if eql[0] == 0:
eql[0] = eql[1]
eql[-1] = eql[-2]
x = np.divide(x[broaden:(nbands - broaden + 1), :],
np.add(np.tile(eql.T, (nframes, 1)).T, 1e-8))
return x, eql
def postaud(x, fmax, fb_type='bark', broaden=0):
"""
do loudness equalization and cube root compression
- x = critical band filters
- rows = critical bands
- cols = frames
"""
nbands, nframes = x.shape
nfpts = int(nbands + 2 * broaden)
if fb_type == 'bark':
bandcfhz = bark2hz(np.linspace(0, hz2bark(fmax), nfpts))
elif fb_type == 'mel':
bandcfhz = mel2hz(np.linspace(0, hz2mel(fmax), nfpts))
elif fb_type == 'htkmel' or fb_type == 'fcmel':
bandcfhz = mel2hz(np.linspace(0, hz2mel(fmax, htk=True), nfpts),
htk=True)
bandcfhz = bandcfhz[broaden:(nfpts - broaden)]
fsq = np.power(bandcfhz, 2)
ftmp = np.add(fsq, 1.6e5)
eql = np.multiply((fsq / ftmp)**2, (fsq + 1.44e6) / (fsq + 9.61e6))
z = np.multiply(np.tile(eql, (nframes, 1)).T, x)
z = np.power(z, 0.33)
if broaden:
y = np.zeros((z.shape[0] + 2, z.shape[1]))
y[0, :] = z[0, :]
y[1:nbands + 1, :] = z
y[nbands + 1, :] = z[z.shape[0] - 1, :]
else:
y = np.zeros((z.shape[0], z.shape[1]))
y[0, :] = z[1, :]
y[1:nbands - 1, :] = z[1:z.shape[0] - 1, :]
y[nbands - 1, :] = z[z.shape[0] - 2, :]
return y, eql
def test_mel2hz(fmel, fhz, htk):
# TO REVISE
if htk == 0:
fmel = np.round(hz2mel(fhz, htk))
fhz = np.round(mel2hz(fmel, htk))
np.testing.assert_almost_equal(mel2hz(fmel, htk), fhz, 0)
def test_hz2mel(fhz, fmel, htk):
if htk == 0:
fhz = np.round(mel2hz(fmel, htk))
np.testing.assert_almost_equal(hz2mel(fhz, htk), fmel, 0)