Add overlay text to videos and concat them to single video using ffmpeg

video_merge.py

#!/usr/bin/env python3
import os, glob

def write_text(input, output, text):
    cmd = f"ffmpeg -i {input} -vf drawtext=\"fontfile=/path/to/font.ttf: text='{text}': fontcolor=white: fontsize=42: box=1: boxcolor=black@0.5: boxborderw=5: x=(w-text_w)/2: y=100\" -codec:a copy {output}"
    print(cmd)
    os.system(cmd)

def merge_videos(folder):
    with open('./input.txt', 'a') as input_file:
        for f in sorted(os.listdir(folder)):
            input_file.write(f"file '{folder}/{f}\n")

    cmd = f"ffmpeg -f concat -i input.txt -codec:a copy concat.mp4"
    print(cmd)
    os.system(cmd)

text_dir_path = "texted"
try:
    os.mkdir(text_dir_path)
except FileExistsError as e:
    print("Directory already exists")

for file in glob.glob("*.mp4"):
    output_file = f"{text_dir_path}/{file}"
    overlay_text = os.path.splitext(file)[0]
    overlay_text = overlay_text[(overlay_text.find('_') + 1):]
    write_text(file, output_file, overlay_text)

merge_videos(text_dir_path)