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import scipy.io.wavfile as sw
import numpy as np
def audio_normalize(y):
"""
Audio data normalization between [-1, 1].
Parameters
----------
y: numpy.ndarray, audio data from SciPy
Returns
----------
norm_y: numpy.ndarray
normalized audio data the range is [-1, 1]
"""
print("y.dtype:", y.dtype)
if y.dtype == "float32" or y.dtype == "float64":
max_y = 1
elif y.dtype == "uint8":
y = y - 128 # convert unsigned to signed
max_y = 128
elif y.dtype == "int16":
max_y = np.abs(np.iinfo(np.int16).min)
elif y.dtype == "int32":
max_y = np.abs(np.iinfo(np.int32).min)
else:
raise ValueError("%s can't use datatype for audio normalization. \
Datatype must be [float32, float64, uint8, int16, int32]" % (y.dtype))
max_y = np.abs(np.iinfo(np.int16).min)
norm_y = y / max_y
norm_y = norm_y.astype(np.float32)
return norm_y
def wavread(wavefile, norm=True):
"""
read wavfile like matlab audioread() function.
Parameters
----------
wavefile: str
wavefile path to read
norm: bool, default:True
audio data normalization settings
call audio_normalize() function
Returns
----------
y: np.ndarray
audio data
fs: int
sampling rate
"""
fs, y = sw.read(wavefile)
if norm:
y = audio_normalize(y)
return (y, fs)
def wavwrite(wavefile, data, fs, ftype="float32"):
"""
write wavfile like matlab audiowrite() function.
Parameters
----------
wavefile: str
wave filepath to write
data: np.ndarray, Audio Data
data.dtype must be [float32, float64, uint8, int16, int32]
fs: sampling rate to write wavefile
ftype: str, default float32
wave filetype specification.
support: [float32(defalut), uint8, int16, int32]
int: integer PCM formats.
float: floating-point formats.
"""
if data.dtype != "float32":
data = audio_normalize(data)
if ftype == "float32":
y = data
elif ftype == "int32":
y = np.int32(data * np.abs(np.iinfo(np.int32).min))
elif ftype == "int16":
y = np.int16(data * np.abs(np.iinfo(np.int16).min))
elif ftype == "uint8":
y = np.int8(data * 128)
y = y + 128 #convert signed to unsigned
else:
print("warning: this function can't support", ftype, ".", wavefile, "was written as float32")
sw.write(wavefile,fs,y)
if __name__ == "__main__":
print("============= norm=True (default) =============")
y, fs = wavread("input.wav")
print("input Datatype:", y.dtype)
wavwrite("output.wav", y, fs)
# confirm output.wav data type
yout, fsout = wavread("output.wav", norm=False)
print("output Datatype:", yout.dtype)
print()
print("============= norm=False and specified datatype of writefile ============")
y, fs = wavread("input.wav", norm=False)
print("input Datatype:", y.dtype)
wavwrite("output.wav", y, fs, ftype="int32")
yout, fsout = wavread("output.wav", norm=False)
# confirm output.wav data typ
print("output Datatype:", yout.dtyp)
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