bug: videos_to_poses crash cv2.error: OpenCV(4.5.5) 👎 error: (-5:Bad argument) in function 'VideoCapture'

[cleong110]

pose/src/python/pose_format/bin/pose_estimation.py

Line 21 in d384d88

cap = cv2.VideoCapture(input_path)

This line expects a string. But our latest version installed from source gives it a pathlib Path here.

Propose fix, cast to str. Change this:

            pose_video(vid_path, pose_path, pose_format, additional_config, progress=False) 

To this:

            pose_video(str(vid_path), str(pose_path), pose_format, additional_config, progress=False) 

Step to replicate:

1. Colab notebook
2. clone repo
3. navigate to the python folder, something like %cd /content/pose/src/python
4. !pip install vidgear mediapipe psutil numpy scipy tqdm "opencv-python==4.5.5.64"
5. !pip install -e. # should output something like install pose-format 0.7
6. also installthe other deps,
7. upload a .mp4 file
8. !videos_to_poses -d directory_containing_the_file

Edit: Here's the traceback:

Traceback (most recent call last):
  File "/usr/lib/python3.10/concurrent/futures/process.py", line 246, in _process_worker
    r = call_item.fn(*call_item.args, **call_item.kwargs)
  File "/usr/lib/python3.10/concurrent/futures/process.py", line 205, in _process_chunk
    return [fn(*args) for args in chunk]
  File "/usr/lib/python3.10/concurrent/futures/process.py", line 205, in <listcomp>
    return [fn(*args) for args in chunk]
  File "/content/pose/src/python/pose_format/bin/directory.py", line 94, in process_video
    pose_video(vid_path, pose_path, pose_format, additional_config, progress=False)
  File "/content/pose/src/python/pose_format/bin/pose_estimation.py", line 21, in pose_video
    cap = cv2.VideoCapture(input_path)
cv2.error: OpenCV(4.5.5) :-1: error: (-5:Bad argument) in function 'VideoCapture'
> Overload resolution failed:
>  - Can't convert object to 'str' for 'filename'
>  - VideoCapture() missing required argument 'apiPreference' (pos 2)
>  - Argument 'index' is required to be an integer
>  - VideoCapture() missing required argument 'apiPreference' (pos 2)

[AmitMY]

fair point! feel free to make that tiny PR :)

[cleong110]

Looking into it further, it seems this was fixed in later versions of OpenCV-Python.

• python: accept path-like objects wherever file names are expected opencv/opencv#24773
• Feature request to add python pathlib Paths to cv2.imread and cv2.imwrite opencv/opencv#15731

So another solution would be to update our requirements to use newer opencv.

But I'll go ahead and do the tiny PR anyway.

[cleong110]

PR made!

Re: OpenCV version:
https://github.com/opencv/opencv/wiki/OpenCV-Change-Logs-v2.2%E2%80%90v4.10#version4100 Looks like after version 4.10 this problem goes away on its own.

@AmitMY do you happen to know why we require such a specific opencv version here? https://github.com/sign-language-processing/pose/blob/master/src/python/pyproject.toml#L22

[AmitMY]

Yes, at some point we had an issue with a new version of opencv, so had to fix the version to something that worked.
Thanks for the fix!