ffmpeg How to fix "Unable to parse option value "/subtitle.ass" as image size"

value "/project/temp/subtitle.ass" as image size     That is wrong

value "D:/project/temp/subtitle.ass" as image size       that is right

 Here's my code

import subprocess
from pathlib import Path

ass_path = r'D:\project\temp\subtitle.ass'


cmd = [
    'ffmpeg',
    '-i', r'D:\pycharm_project\other\original_video.mp4',
    '-vf', f"ass={Path(ass_path).resolve().as_posix()}",
    '-c:v', 'libx264',
    '-crf', '18',
    '-c:a', 'copy',
    '-y',
    'mmmmm.mp4'
]

subprocess.run(cmd, check=True)

 

change the subtitle path to the following:

f"ass={Path(ass_path).resolve().as_posix()}".replace(':','\\\\:') 

finally

import subprocess
from pathlib import Path

ass_path = r'D:\project\ffmpeg_demo\20251106155922.ass'

cmd = [
    'ffmpeg',
    '-i', r'D:\pycharm_project\other\original_video.mp4',
    '-vf', f"ass={Path(ass_path).resolve().as_posix()}".replace(':','\\\\:'),
    '-c:v', 'libx264',
    '-crf', '18',
    '-c:a', 'copy',
    '-y',
    'mmmmm.mp4'
]

subprocess.run(cmd, check=True)

　

Done.