rtsp error(OpenCV(4.2.0) C:\\projects\\opencv-python\\opencv\\modules\\imgcodecs\\src\\loadsave.cpp:715: error: (-215:Assertion failed) !_img.empty() in function cv::imwrite\n,) code example
Example: error: (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'
This error happened because the image didn't load properly.
So you have problem with the previous line cv2.imread my suggestion is :
check if the images exist in the path you give
check the count variable if he have valid number