1
00:00:04,584 --> 00:00:09,609
Hello you !
 
2
00:00:18,393 --> 00:00:23,064
Hello you too

import sys
import re
import traceback
from datetime import datetime, timedelta
 
 
def main():
    try:
        print(sys.getdefaultencoding())
        in_file = open("D:/foo.srt", mode="rt",
                       encoding='utf-8')
        out_file = open("D:/foo-out.srt", mode="at",
                        encoding='utf-8')
        # p_fint(inFile.read())
        lines = [line.strip('\n') for line in in_file]
 
        nb_line_processed = 0
        for line in lines:
            pattern = re.compile(r'(\d\d:\d\d:\d\d,\d\d\d)\s*-->\s*(\d\d:\d\d:\d\d,\d\d\d)')
            match = pattern.match(line)
            if match:
                first_and_second_time = match.groups()
                time_begin = compute_with_delta(first_and_second_time[0], 6.5)
                time_end = compute_with_delta(first_and_second_time[1], 6.5)
                out_file.write(f'{time_begin} --> {time_end}\n')
            else:
                #print(line)
                out_file.write(line + '\n')
            nb_line_processed += 1
        out_file.close()
        print("Done")
        print("nb line processed=", nb_line_processed)
    except Exception:
        print('Exception !')
        print('nb_line_processed=', nb_line_processed)
        print('nb_line_remaining=', len(lines) - nb_line_processed)
        print(traceback.format_exc())
 
 
def compute_with_delta(time, seconds):
    print("before", time)
    # class method : datetime.strptime()
    srt_time_pattern = '%H:%M:%S,%f'
    datetime_object: datetime = datetime.strptime(time, srt_time_pattern) + timedelta(seconds=seconds)
    time_fixed_str = datetime_object.strftime(srt_time_pattern)[:-3]
    try:
        j = 1
    except Exception:
        print("Exception case. time_fixed_str=", time_fixed_str)
        raise
 
    print("after", time_fixed_str)
    return time_fixed_str
 
 
if __name__ == '__main__':
    main()