cap = cv2.VideoCapture(video_path)
if (cap.isOpened() == False):
  print('Error while trying to read video. Please check path again')

# Get the frame width and height.
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))

# Pass the first frame through `letterbox` function to get the resized image,
# to be used for `VideoWriter` dimensions. Resize by larger side.
vid_write_image = letterbox(cap.read()[1], (frame_width), stride=64, auto=True)[0]
resize_height, resize_width = vid_write_image.shape[:2]

save_name = f"{video_path.split('/')[-1].split('.')[0]}"
# Define codec and create VideoWriter object .
out = cv2.VideoWriter(f"{save_name}_keypoint.mp4",
                    cv2.VideoWriter_fourcc(*'mp4v'), 30,
                    (resize_width, resize_height))


frame_count = 0 # To count total frames.
total_fps = 0 # To get the final frames per second.