audio_io.py 文件源码

def wav_data_to_samples(wav_data, sample_rate):
  """Read PCM-formatted WAV data and return a NumPy array of samples.

  Uses scipy to read and librosa to process WAV data. Audio will be converted to
  mono if necessary.

  Args:
    wav_data: WAV audio data to read.
    sample_rate: The number of samples per second at which the audio will be
        returned. Resampling will be performed if necessary.

  Returns:
    A numpy array of audio samples, single-channel (mono) and sampled at the
    specified rate, in float32 format.

  Raises:
    AudioIOReadException: If scipy is unable to read the WAV data.
    AudioIOException: If audio processing fails.
  """
  try:
    # Read the wav file, converting sample rate & number of channels.
    native_sr, y = scipy.io.wavfile.read(six.BytesIO(wav_data))
  except Exception as e:  # pylint: disable=broad-except
    raise AudioIOReadException(e)
  if y.dtype != np.int16:
    raise AudioIOException('WAV file not 16-bit PCM, unsupported')
  try:
    # Convert to float, mono, and the desired sample rate.
    y = int16_samples_to_float32(y)
    if y.ndim == 2 and y.shape[1] == 2:
      y = y.T
      y = librosa.to_mono(y)
    if native_sr != sample_rate:
      y = librosa.resample(y, native_sr, sample_rate)
  except Exception as e:  # pylint: disable=broad-except
    raise AudioIOException(e)
  return y