code: def waveform2melspec(
      waveform, sample_rate, num_mel_bins, target_length
  ):
      # Based on https://github.com/YuanGongND/ast/blob/d7d8b4b8e06cdaeb6c843cdb38794c1c7692234c/src/dataloader.py#L102
      waveform -= waveform.mean()
      fbank = torchaudio.compliance.kaldi.fbank(
          waveform,
          htk_compat=True,
          sample_frequency=sample_rate,
          use_energy=False,
          window_type="hanning",
          num_mel_bins=num_mel_bins,
          dither=0.0,
          frame_length=25,
          frame_shift=DEFAULT_AUDIO_FRAME_SHIFT_MS,
      )
      # Convert to [mel_bins, num_frames] shape
      fbank = fbank.transpose(0, 1)
      # Pad to target_length
      n_frames = fbank.size(1)
      p = target_length - n_frames
      # if p is too large (say >20%), flash a warning
      if abs(p) / n_frames > 0.2:
          logging.warning(
              "Large gap between audio n_frames(%d) and "
              "target_length (%d). Is the audio_target_length "
              "setting correct?",
              n_frames,
              target_length,
          )
      # cut and pad
      if p > 0:
          fbank = torch.nn.functional.pad(
              fbank, (0, p), mode="constant", value=0
          )
      elif p < 0:
          fbank = fbank[:, 0:target_length]
      # Convert to [1, mel_bins, num_frames] shape, essentially like a 1
      # channel image
      fbank = fbank.unsqueeze(0)
      return fbank
  
imports: import logging
  import math
  import torch
  import torch.nn
  import torchaudio
  from PIL import Image
  from pytorchvideo import transforms
  from pytorchvideo.data.clip_sampling import ConstantClipsPerVideoSampler
  from pytorchvideo.data.encoded_video import EncodedVideo
  from torchvision import transforms
  from torchvision.transforms._transforms_video import NormalizeVideo
  from imagebind.models.multimodal_preprocessors import SimpleTokenizer
label_desc: Use image node_id 1 for calling a global function with example usage: waveform2melspec(waveform, sample_rate, num_mel_bins, target_length) and returns: fbank