Load HTK parameter/feature file.

    :param input_filename:
    :param only_header: only load the metadata
    :return: a named tuple representing the HTK parmeter file

def load_parameter(input_filename, only_header=False):
    """Load HTK parameter/feature file.

    :param input_filename:
    :param only_header: only load the metadata
    :return: a named tuple representing the HTK parmeter file
    """

    with open(input_filename, 'rb') as f:
        meta = _parse_parameter_meta(f)
        if only_header:
            return meta

        return _parse_parameter_samples(f, meta)