If you call ffmpeg-python like this:

import ffmpeg
stream = ffmpeg.input('input.mp4')
stream = ffmpeg.output(stream, 'output.mp4')
ffmpeg.run(stream, overwrite_output=False)

You can provide the overwrite_output keyword when calling run or other 'output' methods.
Here is the option in the source code for the run method: https://github.com/kkroening/ffmpeg-python/blob/master/ffmpeg/_run.py#L297
Note that 'False' is already the default. If you simply do not specify it it will not overwrite it.
The other output_operators also have that keyword.

@153957

Note that 'False' is already the default. If you simply do not specify it it will not overwrite it.

I was not able to confirm this behavior. overwrite_output=False acts as if neither -y nor -n was specified, making it ask interactively and then error out when file exists, whereas one would expect overwrite_output=False to just not overwrite the file.

Current behavior:

• overwrite_output=False -> asks interactively, errors out when not overwriting
• overwrite_output=True -> overwrites (-y)
• overwrite_output not specified -> same as overwrite_output=False

Expected (intuitive) behavior:

• overwrite_output=False -> does not overwrite (-n)
• overwrite_output=True -> overwrites (-y)
• overwrite_output not specified (perhaps the default should be overwrite_output=None) -> errors out when file exists