code: def powspec_feat(
      samples,
      sr=8000,
      nfft=512,
      winlen=0.025,
      winstep=0.010,
      lowfreq=0,
      highfreq=None,
      preemph=0.97,
  ):
      """
      params:
        samples: [nsample, channels]
      returns:
        powspec: power spectrogram, shape [channels, nframe, nfft / 2 + 1]
      """
      del nfft
      del lowfreq
      del highfreq
      del preemph
  
      # pylint: disable=no-member
      feat = audio_ops.audio_spectrogram(
          samples,
          window_size=winlen * sr,
          stride=winstep * sr,
          magnitude_squared=True,
      )
      return feat
  
file_path: delta/delta/data/feat/speech_ops.py
imports: import numpy
  from absl import logging
  import delta.compat
  from tensorflow.python.ops import gen_audio_ops
  from delta import utils
  from delta.utils.hparam import HParams
  from core.ops import py_x_ops
label_desc: Use image node_id 3 for calling a global function with example usage: powspec_feat(samples, sr, nfft, winlen, winstep, lowfreq, highfreq, preemph) and returns: feat