In the code, first I'm opening wav file called output_test.wav. I then filter the noise from the signal using fftpack.
Problem: I'm trying to convert the filtered signal i.e. filtered_sig
array into wav file properly. Currently when I open TestFiltered.wav I get the error:
The item was encoded into a format not supported: 0xc00d5212
Upon further investigation it seems I'm not filtering noise correctly?
I think the error comes from the last 2 lines:
filteredwrite = np.fft.irfft(filtered_sig, axis=0)
wavfile.write('TestFiltered.wav', frame_rate, filteredwrite)
CODE:
import numpy as np
from scipy import fftpack
import pyaudio
import wave
from scipy.io import wavfile
def playback():
CHUNK = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 2
RATE = 44100
RECORD_SECONDS = 8
WAVE_OUTPUT_FILENAME = "output.wav"
filename = 'output_test.wav'
# Set chunk size of 1024 samples per data frame
chunk = 1024
# Open the sound file
wf = wave.open(filename, 'rb')
frame_rate = wf.getframerate()
wf_x = wf.readframes(-1)
signal = np.frombuffer(wf_x, dtype='int16')
#print("signalxx", signal)
return [signal, frame_rate]
time_step = 0.5
# get the data
data = playback()
sig = data[0]
frame_rate = data[1]
# Return discrete Fourier transform of real or complex sequence
sig_fft = fftpack.fft(sig) # tranform the sin function
# Get Amplitude ?
Amplitude = np.abs(sig_fft) # np.abs() - calculate absolute value from a complex number a + ib
Power = Amplitude**2 # create a power spectrum by power of 2 of amplitude
# Get the (angle) base spectrum of these transform values i.e. sig_fft
Angle = np.angle(sig_fft) # Return the angle of the complex argument
# For each Amplitude and Power (of each element in the array?) - there is will be a corresponding difference in xxx
# This is will return the sampling frequecy or corresponding frequency of each of the (magnitude) i.e. Power
sample_freq = fftpack.fftfreq(sig.size, d=time_step)
print(Amplitude)
print(sample_freq)
# Because we would like to remove the noise we are concerned with peak freqence that contains the peak amplitude
Amp_Freq = np.array([Amplitude, sample_freq])
# Now we try to find the peak amplitude - so we try to extract
Amp_position = Amp_Freq[0,:].argmax()
peak_freq = Amp_Freq[1, Amp_position] # find the positions of max value position (Amplitude)
# print the position of max Amplitude
print("--", Amp_position)
# print the frequecies of those max amplitude
print(peak_freq)
high_freq_fft = sig_fft.copy()
# assign all the value the corresponding frequecies larger than the peak frequence - assign em 0 - cancel!! in the array (elements) (?)
high_freq_fft[np.abs(sample_freq) > peak_freq] = 0
print("yes:", high_freq_fft)
# Return discrete inverse Fourier transform of real or complex sequence
filtered_sig = fftpack.ifft(high_freq_fft)
# Using Fast Fourier Transform and inverse Fast Fourier Transform we can remove the noise from the frequency domain (that would be otherwise impossible to do in Time Domain) - done.
print("filtered noise: ", filtered_sig)
print("getiing frame rate $$", frame_rate)
filteredwrite = np.fft.irfft(filtered_sig, axis=0)
print (filteredwrite)
wavfile.write('TestFiltered.wav', frame_rate, filteredwrite)
Any ideas?
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