Source code for util.audio

import numpy as np
import scipy.io.wavfile as wav

from python_speech_features import mfcc


[docs]def audiofile_to_input_vector(audio_filename, numcep, numcontext): r""" Given a WAV audio file at ``audio_filename``, calculates ``numcep`` MFCC features at every 0.01s time step with a window length of 0.025s. Appends ``numcontext`` context frames to the left and right of each time step, and returns this data in a numpy array. """ # Load wav files fs, audio = wav.read(audio_filename) # Get mfcc coefficients features = mfcc(audio, samplerate=fs, numcep=numcep) # We only keep every second feature (BiRNN stride = 2) features = features[::2] # Add empty initial and final contexts empty_context = np.zeros((numcontext, numcep), dtype=features.dtype) features = np.concatenate((empty_context, features, empty_context)) return features