Script to cleanup SRT transcripts. Run like `python3 clean.py input.srt output.srt`

clean.py

from collections import namedtuple
from pprint import pprint
import math
import sys


Caption = namedtuple('Caption', ['start', 'end', 'text'])

def parse(l):
    lines = l.split('\n')
    start, end = lines[1].split(' --> ')
    text = '\n'.join(lines[2:]).strip()
    return Caption(start, end, text)

def fix_puncuation(lines):
    new_lines = []
    for i, l in enumerate(lines):
        if i == 0 or len(l) == 1:
            new_lines.append(l)
            continue
        if new_lines[-1].end == l.start:
            if (not l.text[0].isalpha()) and l.text[1] == ' ':
                new_lines[-1] = Caption(new_lines[-1].start, new_lines[-1].end, new_lines[-1].text.strip() + l.text[0])
                new_lines.append(Caption(l.start, l.end, l.text[2:].strip()))
                continue
            if len(l.text) <= 3:
                if l.text[0].isalnum():
                    new_lines[-1] = Caption(new_lines[-1].start, l.end, new_lines[-1].text.strip() + ' ' + l.text)
                else:
                    new_lines[-1] = Caption(new_lines[-1].start, l.end, new_lines[-1].text.strip() + l.text)
                continue
        new_lines.append(l)
    return new_lines


def split42(t):
    if len(t) <= 42:
        return t
    i = t.rfind(' ', 0, 42)
    if i < 0:
        i = 42
    return t[:i].strip() + '\n' + split42(t[i:].strip()).strip()


def fix_length(lines):
    if not any(len(l.text) > 42 for l in lines):
        return lines
    new_lines = []
    for l in lines:
        # if len(l.text) > 42:
        #     i = l.text.rfind(' ', 0, 42)
        #     if i < 0:
        #         i = 42
        #     text = l.text[:i].strip() + '\n' +
        new_lines.append(Caption(l.start, l.end, split42(l.text)))
            # a = make_time(l.start)
            # b = make_time(l.end)
            # c = a + (b - a) * i / len(l.text)
            # new_lines.append(Caption(time_str(a), time_str(c), l.text[:i].strip()))
            # new_lines.append(Caption(time_str(c), time_str(b), l.text[i:].strip()))
        # else:
        #     new_lines.append(l)
    return new_lines


def clean(lines):
    new_lines = []
    for l in lines:
        if '[' in l.text or '(' in l.text or ']' in l.text or ')' in l.text:
            continue
        if not new_lines:
            new_lines.append(l)
            continue
        if new_lines[-1].text.strip() == l.text.strip():
            if new_lines[-1].end == l.start:
                new_lines[-1] = Caption(new_lines[-1].start, l.end, new_lines[-1].text)
                continue
        if len(l.text.strip()) == 1:
            new_lines[-1] = Caption(new_lines[-1].start, l.end, new_lines[-1].text.strip() + l.text.strip())
            continue
        new_lines.append(l)
    return fix_puncuation(fix_length(new_lines))


def make_time(x):
    """
    >>> make_time('01:01:06,123')
    3666.123
    """
    seconds, millis = x.strip().split(',')
    h, m, s = seconds.split(':')
    return int(h) * 3600 + int(m) * 60 + int(s) + int(millis) / 1000


def time_str(x):
    """
    >>> time_str(3666.123)
    '01:01:06,123'
    """
    seconds = int(math.floor(x))
    millis = int((x - seconds) * 1000)
    h = seconds // 3600
    m = (seconds % 3600) // 60
    s = seconds % 60
    return f'{h:02d}:{m:02d}:{s:02d},{millis:03d}'

if __name__ == '__main__':
    if len(sys.argv) < 2:
        print('Usage: python3 clean.py input output')
        sys.exit(1)

    print(sys.argv[1])
    lines = []

    with open(sys.argv[1], 'rb') as fin:
        txt = fin.read().decode('utf-8', errors='ignore')

    lines = [parse(l.strip()) for l in txt.split('\n\n') if len(l.strip()) > 0]
    # pprint(lines)

    lines = clean(lines)

    times = []
    for i, line in enumerate(lines):
        times.append((i, make_time(line.start), make_time(line.end)))

    for i, start, end in times[1:]:
        for j in range(i):
            if times[j][2] > start:
                print(f'overlap: {j} x {i}: {lines[j].text} {lines[i].text}')

    check = False

    with open(sys.argv[2], 'w') as fout:
        for i, line in enumerate(lines):
            fout.write(f'{i+1}\n{line.start} --> {line.end}\n{line.text}\n\n')
            if i > 0 and not check:
                if lines[i-1].text.strip() == line.text.strip():
                    print(f'check: {i}: {line.text.strip()}')
                    check = True