Index is slice ID

def get_blob(self, index):
        """Index is slice ID"""
        blob = self._current_blob
        self.r.retrieve_timeslice(index)
        timeslice_info = Table.from_template({
            'frame_index': self.r.frame_index,
            'slice_id': index,
            'timestamp': self.r.utc_seconds,
            'nanoseconds': self.r.utc_nanoseconds,
            'n_frames': self.r.n_frames,
        }, 'TimesliceInfo')
        hits = self._extract_hits()
        hits.group_id = index
        blob['TimesliceInfo'] = timeslice_info
        blob[self._hits_blob_key] = hits
        return blob