Using a Pascal wrapper for OpenCV, your core code to open a camera and show a window would look like this:
Raspberry Pis (especially older models) may struggle with 1080p processing in real-time. Stick to 640x480 for smoother frame rates during testing. Pascal Webcam Raspberry
If you are doing heavy lifting, look into the V4L2 memory mapping ( mmap ) to pass frames directly to the GPU. Helpful Resources Using a Pascal wrapper for OpenCV, your core
Best for face detection, motion tracking, or filters. You will need the Pascal headers for OpenCV (often found in the OpenCV-Pascal or Lazarus-ccr repositories). Using a Pascal wrapper for OpenCV