def pad_utterance(utt_tensor, diarization, spkidx, meeting_scale, start):
    """Pads utterance to meeting length.

    Args:
      utt_tensor: Utterance with shape (num_mics, max_utt_length).
      diarization: Diarization with shape (max_dia_seg_per_utt, 2).
      spkidx: Speaker index (global) for the utterance.
      meeting_scale: Target meeting scale.
      start: Start index of utterance in the meeting.
    Returns:
      utt_tensor_padded: Padded utt tensor (num_mics, samples + max_utt_length)
      diarization_padded: Diarization updated using the start index.
      spkidx: Speaker index passed unchanged.
      meeting_scale: Target meeting scale passed unchanged.
    """
    start = start[0]
    end_paddings = samples - start
    utt_tensor_padded = tf.pad(utt_tensor, ((0, 0), (start, end_paddings)))
    diarization_padded = start + diarization
    return utt_tensor_padded, diarization_padded, spkidx, meeting_scale