subtitle_synchronizer.py

def convertToMilliseconds(time):
    milliseconds = 0
    hh,mm,ms = time.split(":")
    ms = ms.strip().replace(",","")
    hh = int(hh)
    mm = int(mm)
    ms = int(ms)

    milliseconds = hh*3600000+mm*60000+ms
    return milliseconds

def synchronize(time,shift):
    return time-shift

def convertToTime(milliseconds):
    hh = milliseconds//3600000
    milliseconds = milliseconds%3600000
    hh = str(hh)
    if len(hh) < 2: hh = "0"+hh

    mm = milliseconds//60000
    milliseconds = milliseconds%60000
    mm = str(mm)
    if len(mm) < 2: mm = "0"+mm

    ss = milliseconds//1000
    milliseconds = milliseconds%1000
    ss = str(ss)
    if len(ss) < 2: ss = "0"+ss

    milliseconds = str(milliseconds)
    while len(milliseconds) < 3:
        milliseconds = "0"+milliseconds

    return f"{hh}:{mm}:{ss},{milliseconds}"


def main():
    SHIFT = int(input("Please enter the shift in milliseconds: "))
    f = open("input.txt", "r", errors="ignore")
    output = open("output.txt","a")
    for x in f:
        if "-->" in x:
            start,end = x.split("-->")
            start,end = convertToMilliseconds(start), convertToMilliseconds(end)
            start,end = synchronize(start,SHIFT),synchronize(end,SHIFT)
            start,end = convertToTime(start),convertToTime(end)
            output.write(f"{start} --> {end}\n")
        else:
            output.write(x)


#Right click the subtitles file you want to synchronize and open it in a notepad
#Then copy all of its content and paste it into a new file and name it as "input.txt"

#You must have your "input.txt" in the same folder as this program

#Once you run this program you will be asked to enter a shift in milliseconds.

#You can find the shift when you are watching the video as it is impossible to
#determine that using any program since it is variable for every video.

#Once the program has finished running, you will have your subtitles synchronized
#in a file that says "output.txt". Copy its content and paste it into your original subtitles file.
main()