code: def mulaw_encode(wav, qc):
      mu = 2**qc - 1
      # wav_abs = np.minimum(np.abs(wav), 1.0)
      signal = (
          np.sign(wav) * np.log(1 + mu * np.abs(wav)) / np.log(1.0 + mu)
      )
      # Quantize signal to the specified number of levels.
      signal = (signal + 1) / 2 * mu + 0.5
      return np.floor(
          signal,
      )
  
imports: import librosa
  import soundfile
  import numpy
  import scipy.io.wavfile
  import scipy.signal
  from TTS.tts.utils.data import StandardScaler
label_desc: Use image node_id 28 for calling the AudioProcessor obj's underlying member method code with example usage: obj.mulaw_encode(wav, qc) and returns: np