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Fix lowpass_filter method via clamping down frequency #7

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Fix lowpass_filter method via clamping down frequency #7

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18 changes: 11 additions & 7 deletions FlashSR/Util/UtilAudioLowPassFilter.py
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Original file line number Diff line number Diff line change
Expand Up @@ -37,14 +37,18 @@ def lowpass(audio:ndarray, #[time] 1d array

@staticmethod
def lowpass_filter(x:ndarray, #[time] 1d array
highcutoff_freq:float, #high cutoff frequency
fs:int,
order:int, #the order of filter
ftype:Literal['butter', 'cheby1', 'cheby2', 'ellip', 'bessel'],
upsample_to_original:bool = True
) -> ndarray: #[time] 1d array
highcutoff_freq:float, #high cutoff frequency
fs:int,
order:int, #the order of filter
ftype:Literal['butter', 'cheby1', 'cheby2', 'ellip', 'bessel'],
upsample_to_original:bool = True
) -> ndarray: #[time] 1d array
nyq = 0.5 * fs
# Ensure hi is between 0 and 1 (exclusive)
hi = highcutoff_freq / nyq
hi = min(hi, 0.999) # Clamp to just below 1
hi = max(hi, 0.001) # Clamp to just above 0

if ftype == "butter":
sos = butter(order, hi, btype="low", output="sos")
elif ftype == "cheby1":
Expand Down Expand Up @@ -106,4 +110,4 @@ def subsampling(data, lowpass_ratio, fs_ori=44100, upsample_to_original:bool = T

if __name__ == "__main__":
util = UtilAudioLowPassFilter()
util.lowpass(np.zeros(24000),48000, filter_name="cheby", filter_order=8, cutoff_freq=8000)
util.lowpass(np.zeros(24000),48000, filter_name="cheby", filter_order=8, cutoff_freq=8000)