Extracting thumbnail Image of raw photo file yield UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte

[bird1e222]

Hi,

I'm trying to run the following exiftool command to extract a thumbnail image of a raw photo file, using pyexiftool:

exiftool -b -ThumbnailImage raw_image.ARW > thumbnail_image.jpg

It works just fine when I run it from terminal, and it does extract the thumbnail image from the raw file.
But when I try to run it with pyexiftool, using this code:

from exiftool import ExifToolHelper

params = ["-b", "-ThumbnailImage", "raw_file.ARW", ">", "thumbnail_image.jpg"]

with ExifToolHelper() as et:
    et.execute(*params)

I get the following error message (where line 6 is the last line of my code):

Traceback (most recent call last):
  File "/Users/test_folder/simple_test.py", line 6, in <module>
    et.execute(*params)
  File "/Users/michelsabourin/.pyenv/versions/3.12.1/lib/python3.12/site-packages/exiftool/helper.py", line 131, in execute
    result: Union[str, bytes] = super().execute(*str_bytes_params, **kwargs)
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/michelsabourin/.pyenv/versions/3.12.1/lib/python3.12/site-packages/exiftool/exiftool.py", line 1067, in execute
    raw_stdout = raw_stdout.decode(self._encoding)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte

I searched Internet for a solution and found many mentions of this error message, but could not figure out how they would apply to my problem.

I did however manage to find out the encoding of my raw file using this bit of code (don't know if it helps):

import chardet

with open("raw_file.ARW", "rb") as rawdata:
    result = chardet.detect(rawdata.read(10000))
print(result)

{'encoding': 'MacRoman', 'confidence': 0.6785735165156387, 'language': ''}

I'm running:
PyExifTool version: 0.5.6
exiftool version 12.70
Python version 3.12.1

Can somebody help me, please?
Thank you!