code: def load_wav(wavpath, sr=8000):
      """
      audio:
        np.float32, shape [None], sample in [-1, 1], using librosa.load
        np.int16, shape [None], sample in [-32768, 32767], using scipy.io.wavfile
        np.float32, shape[None, audio_channel], sample int [-1, 1], using tf.DecodeWav
  
      return
        sr: sample rate
        audio: [-1, 1], same to tf.DecodeWav
      """
      # from scipy.io import wavfile
      # sample_rate, audio = wavfile.read(wavpath)
  
      # samples, sample_rate = librosa.load(wavpath, sr=sr)
  
      feat_name = "load_wav"
      graph = None
      # get session
      if feat_name not in _global_sess:
          graph = tf.Graph()
          with graph.as_default():
              params = speech_ops.speech_params(
                  sr=sr, audio_desired_samples=-1
              )
              t_wavpath = tf.placeholder(
                  dtype=tf.string, name="wavpath"
              )
              t_audio, t_sample_rate = speech_ops.read_wav(
                  t_wavpath, params
              )
              t_audio = tf.identity(t_audio, name="audio")
              t_sample_rate = tf.identity(
                  t_sample_rate, name="sample_rate"
              )
  
      sess = _get_session(feat_name, graph)
      audio, sample_rate = sess.run(
          [
              _get_out_tensor_name("audio", 0),
              _get_out_tensor_name("sample_rate", 0),
          ],
          feed_dict={"wavpath:0": wavpath},
      )
      audio = audio[:, 0]
  
      assert (
          sample_rate == sr
      ), "sampling rate must be {}Hz, get {}Hz".format(sr, sample_rate)
      return sample_rate, audio
  
file_path: delta/delta/data/feat/speech_feature.py
imports: import os
  import numpy
  import delta.compat
  from absl import logging
  from delta.data.feat import speech_ops
  from core.ops import py_x_ops
  from delta.data.feat import python_speech_features
label_desc: Use image node_id 6 for calling a global function with example usage: load_wav(wavpath, sr) and returns: sample_rate,  audio