docstr: Check that HIFIGAN_VOCODER_V3_LJSPEECH.get_mel_transform generates the same mel spectrogram as the original
  HiFiGAN implementation when applied on a synthetic waveform.
  There seems to be no way to change dtype in the original implmentation, so we feed in the waveform with the
  default dtype and cast the output before comparison.
docstr_tok: ["Check","that","HIFIGAN_VOCODER_V3_LJSPEECH.get_mel_transform","generates","the","same","mel","spectrogram","as","the","original","HiFiGAN","implementation","when","applied","on","a","synthetic","waveform",".","There","seems","to","be","no","way","to","change","dtype","in","the","original","implmentation",",","so","we","feed","in","the","waveform","with","the","default","dtype","and","cast","the","output","before","comparison","."]
code: def test_mel_transform(self):
      """Check that HIFIGAN_VOCODER_V3_LJSPEECH.get_mel_transform generates the same mel spectrogram as the original
      HiFiGAN implementation when applied on a synthetic waveform.
      There seems to be no way to change dtype in the original implmentation, so we feed in the waveform with the
      default dtype and cast the output before comparison.
      """
      synth_waveform = torch.rand(1, 1000).to(device=self.device)
  
      # Get HiFiGAN-compatible transformation from waveform to mel spectrogram
      self.mel_spectrogram = (
          HIFIGAN_VOCODER_V3_LJSPEECH.get_mel_transform().to(
              dtype=self.dtype, device=self.device
          )
      )
      mel_spec = self.mel_spectrogram(
          synth_waveform.to(dtype=self.dtype)
      )
      # Generate mel spectrogram with original implementation
      ref_mel_spec = ref_mel_spectrogram(
          synth_waveform,
          n_fft=self.mel_spectrogram.n_fft,
          num_mels=self.mel_spectrogram.n_mels,
          sampling_rate=self.mel_spectrogram.sample_rate,
          hop_size=self.mel_spectrogram.hop_size,
          win_size=self.mel_spectrogram.win_length,
          fmin=self.mel_spectrogram.f_min,
          fmax=self.mel_spectrogram.f_max,
      )
      self.assertEqual(
          ref_mel_spec.to(dtype=self.dtype),
          mel_spec,
          atol=1e-5,
          rtol=1e-5,
      )
  
imports: import math
  import torch
  from parameterized import parameterized
  from torchaudio.prototype.models import hifigan_vocoder, hifigan_vocoder_v1, hifigan_vocoder_v2, hifigan_vocoder_v3
  from torchaudio.prototype.pipelines import HIFIGAN_VOCODER_V3_LJSPEECH
  from torchaudio_unittest.common_utils import TestBaseMixin, torch_script
  from .original.env import AttrDict
  from .original.meldataset import mel_spectrogram
  from .original.models import Generator
label_desc: Use image node_id 10 for calling the HiFiGANTestImpl obj's underlying member method code with example usage: obj.test_mel_transform() without return types