def file_duration_parser(line):
    """
    Parses lines of the following form: extracts only the seconds part

        File duration: 5248.68s (100.00%)

    :param line: string
    :return: float containing the duration for the file in seconds
    """
    line = line[len('File duration:'):]
    ie = line.find('s')
    try:
        return float(line[:ie])
    except:
        return 0.