Rename subtitle files for TV series to match the video filename

rename_sub.py

import os
import re

episodes = {}
regex = re.compile(r"(S(\d+))?EP?(\d+)", re.IGNORECASE)

for root, dirs, files in os.walk("."):
    for f in files:
        if f.endswith(".mp4") or f.endswith(".mkv"):
            m = regex.search(f)
            if m:
                season = 1
                if m.group(2):
                    season = int(m.group(2))
                episode = int(m.group(3))
                episodes[f'S{season}E{episode}'] = f

for root, dirs, files in os.walk("."):
    for f in files:
        if f.endswith(".ass") or f.endswith(".srt"):
            m = regex.search(f)
            if m:
                season = 1
                if m.group(2):
                    season = int(m.group(2))
                episode = int(m.group(3))

                filename = episodes[f'S{season}E{episode}'][:-4]
                new_filename = f[:-4]
                if filename == new_filename:
                    continue

                old_name = os.path.join(root, f)
                new_name = os.path.join(root, filename + f[-4:])
                print(f"{old_name} => {new_name}")
                os.rename(old_name, new_name)