[英]calculating FFT in frames and writing to a file
我是 python 的新手,我正在嘗試獲取上傳的 wav 文件的 FFT 值並返回文本文件每一行中每一幀的 FFT(使用 GCP)
使用 scipy 或 librosa
我需要的幀速率是 30fps
波形文件將是 48k 采樣率
所以我的問題是
您可以使用帶有回調的 pyaudio 來實現您正在做的任何事情。
import pyaudio
import wave
import time
import struct
import sys
import numpy as np
if len(sys.argv) < 2:
print("Plays a wave file.\n\nUsage: %s filename.wav" % sys.argv[0])
sys.exit(-1)
wf = wave.open(sys.argv[1], 'rb')
# instantiate PyAudio (1)
p = pyaudio.PyAudio()
def callback_test(data, frame_count, time_info, status):
frame_count =1024
elm = wf.readframes(frame_count) # read n frames
da_i = np.frombuffer(elm, dtype='<i2') # convert to little endian int pairs
da_fft = np.fft.rfft(da_i) # fast fourier transform for real values
da_ifft = np.fft.irfft(da_fft) # inverse fast fourier transform for real values
da_i = da_ifft.astype('<i2') # convert to little endian int pairs
da_m = da_i.tobytes() # convert to bytes
return (da_m, pyaudio.paContinue)
# open stream using callback (3)
stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
channels=wf.getnchannels(),
rate=wf.getframerate(),# sampling frequency
output=True,
stream_callback=callback_test)
# # start the stream (4)
stream.start_stream()
# # wait for stream to finish (5)
while stream.is_active():
time.sleep(0.1)
# # stop stream (6)
stream.stop_stream()
stream.close()
wf.close()
# close PyAudio (7)
p.terminate()
請參閱這些鏈接以進行進一步研究:
https://people.csail.mit.edu/hubert/pyaudio/docs/#example-callback-mode-audio-io和Python 更改 wav 文件的音高
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