Adjust the SRT (subtitle) file time in milliseconds

srt_adjust.py

"""
**HOW TO INSTALL:**

pip3 install srt_adjust

**HOW TO USE:**

srt_adjust file.srt 1000

**FOR MORE INFORMATION:**

https://github.com/six519/srt_adjust

"""
import re
import sys
from datetime import (
    datetime,
    timedelta,
)

modified_file = []
time_format = '%H:%M:%S.%f'


def add_ms(time_str, milliseconds):
    dt_obj = datetime.strptime(time_str, time_format)
    dt_obj += timedelta(milliseconds=int(milliseconds))
    return dt_obj.time().strftime(time_format)[:-3].replace('.', ',')


if __name__ == '__main__' and len(sys.argv) > 2:

    try:
        with open(sys.argv[1], 'r') as file:
            for line in file:
                line = line.strip()
                if re.match(r'[0-9]{2}:[0-9]{2}:[0-9]{2},[0-9]{3}', line):
                    frm, to = line.replace(',', '.').split(' --> ')
                    frm = add_ms(frm, sys.argv[2])
                    to = add_ms(to, sys.argv[2])
                    line = f'{frm} --> {to}'

                modified_file.append(line)

            with open(f'mod_{sys.argv[1]}', 'w') as file:
                for line in modified_file:
                    file.write(f'{line}\n')
            
            print(f'Adjusted srt file: mod_{sys.argv[1]}\n')
    except FileNotFoundError:
        print(f'Unable to open srt file: {sys.argv[1]}\n')
    except ValueError:
        print(f'Invalid time value: {sys.argv[2]}\n')