def return_hdr(self):
        """Return the header for further use.

        Returns
        -------
        subj_id : str
            subject identification code
        start_time : datetime
            start time of the dataset
        s_freq : float
            sampling frequency
        chan_name : list of str
            list of all the channels
        n_samples : int
            number of samples in the dataset
        orig : dict
            additional information taken directly from the header

        """
        orig = {}
        for xml_file in self.filename.glob('*.xml'):
            if xml_file.stem[0] != '.':
                orig[xml_file.stem] = parse_xml(str(xml_file))

        signals = sorted(self.filename.glob('signal*.bin'))

        for signal in signals:
            block_hdr, i_data = read_all_block_hdr(signal)
            self._signal.append(signal)
            self._block_hdr.append(block_hdr)
            self._i_data.append(i_data)
            n_samples = asarray([x['n_samples'][0] for x in block_hdr], 'q')
            self._n_samples.append(n_samples)

        try:
            subj_id = orig['subject'][0][0]['name']
        except KeyError:
            subj_id = ''
        try:
            start_time = datetime.strptime(orig['info'][0]['recordTime'][:26],
                                           '%Y-%m-%dT%H:%M:%S.%f')
        except KeyError:
            start_time = DEFAULT_DATETIME
        self.start_time = start_time

        videos = (list(self.filename.glob('*.mp4')) +  # as described in specs
                  list(self.filename.glob('*.mov')))  # actual example
        videos = [x for x in videos if x.stem[0] != '.']  # remove hidden files

        if len(videos) > 1:
            lg.warning('More than one video present: ' + ', '.join(videos))
        self._videos = videos

        # it only works if they have all the same sampling frequency
        s_freq = [x[0]['freq'][0] for x in self._block_hdr]
        assert all([x == s_freq[0] for x in s_freq])
        SIGNAL = 0
        s_freq = self._block_hdr[SIGNAL][0]['freq'][0]
        n_samples = sum(self._n_samples[SIGNAL])

        chan_name, self._nchan_signal1 = _read_chan_name(orig)
        self._orig = orig

        return subj_id, start_time, s_freq, chan_name, n_samples, orig
Return the header for further use.

        Returns
        -------
        subj_id : str
            subject identification code
        start_time : datetime
            start time of the dataset
        s_freq : float
            sampling frequency
        chan_name : list of str
            list of all the channels
        n_samples : int
            number of samples in the dataset
        orig : dict
            additional information taken directly from the header