from scipy.io import wavfile
import imageio
import numpy as np

rate, data = wavfile.read("PCT-15_AUDIO.wav")
# convert to complex
data = data.astype(np.complex64)
# center the signal frequency
data *= (-1+0j) ** (np.arange(len(data)) * (2*1747.805/rate))
# low pass filter using sinc (without proper windowing, probably stupid)
space = (np.arange(-100, 101) + .5) * (1500 / rate)
lpf = np.sin(np.pi*space) / (np.pi * space)
data = np.convolve(data, lpf, mode="same")
# align with real axis
data *= (-1)**.175
# align x axis
data = data[1930:]
# 1d -> 2d
n = 2422 # width of image
data = data[:len(data)//n*n]
data = data.reshape((-1, n))
# cut off emty parts
data = data[34:-24]
# use only real part
data = data.real
# get in range [0, 1]
data = data - np.percentile(data, .5)
data /= np.percentile(data, 99.5)
data = data.clip(0,1)
# fix aspect ratio
data = data.repeat(30, axis=0)
# write to file
imageio.imwrite("test2.png", data)