Return the map
        from the MFCC speech frame indices
        in the MIDDLE portion of the wave
        to the MFCC FULL frame indices.

        :rtype: :class:`numpy.ndarray` (1D)

def masked_middle_map(self):
        """
        Return the map
        from the MFCC speech frame indices
        in the MIDDLE portion of the wave
        to the MFCC FULL frame indices.

        :rtype: :class:`numpy.ndarray` (1D)
        """
        begin, end = self._masked_middle_begin_end()
        return self.__mfcc_mask_map[begin:end]