class_docstr: MelSpectrum extraction test.
code: def test_mel_spectrum(self):
      # 16kHz test
      wav_path_16k = str(
          Path(PACKAGE_OPS_DIR).joinpath("data/sm1_cln.wav")
      )
  
      with self.cached_session(use_gpu=False, force_gpu=False):
          # value test
          read_wav = ReadWav.params().instantiate()
          input_data, sample_rate = read_wav(wav_path_16k)
          print(sample_rate.eval())
          config = {
              "type": "MelSpectrum",
              "window_type": "hann",
              "upper_frequency_limit": 7600,
              "filterbank_channel_count": 80,
              "lower_frequency_limit": 80,
              "dither": 0.0,
              "window_length": 0.025,
              "frame_length": 0.010,
              "remove_dc_offset": False,
              "preEph_coeff": 0.0,
              "output_type": 3,
              "sample_rate": 16000,
          }
          mel_spectrum = MelSpectrum.params(config).instantiate()
          mel_spectrum_test = mel_spectrum(input_data, sample_rate)
          print(mel_spectrum_test.eval()[0:2, 0:10])
  
file_path: delta/delta/data/frontend/mel_spectrum_test.py
imports: from pathlib import Path
  import delta.compat
  from core.ops import PACKAGE_OPS_DIR
  from delta.data.frontend.read_wav import ReadWav
  from delta.data.frontend.mel_spectrum import MelSpectrum
label_desc: Use image node_id 1 for calling the MelSpectrumTest obj's underlying member method code with example usage: obj.test_mel_spectrum() without return types