I'm trying to crop a video, using Python 3+, by reading it frame-by-frame and write certain frames to a new video.
I want to use GPU to speed up this process, as for a 1h video, it would take my CPU ~24h to complete.
My understanding is, Reading a video using CPU:
vid = cv2.VideoCapture(vid_path)
fps = int(vid.get(cv2.CAP_PROP_FPS))
total_num_frames = int(vid.get(cv2.CAP_PROP_FRAME_COUNT))
frame_width = int(vid.get(cv2.CAP_PROP_FRAME_WIDTH))
frame_height = int(vid.get(cv2.CAP_PROP_FRAME_HEIGHT))
Writing a video using CPU:
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
new_vid = cv2.VideoWriter(new_vid_path, fourcc, fps, (frame_width, frame_height))
Reading a frame on CPU, uploading & downloading it to/from GPU, then writing it using CPU:
ret, frame = vid.read()
gpu_frame = cv2.cuda_GpuMat()
gpu_frame.upload(frame)
frame = gpu_frame.download()
new_vid.write(frame)
Note: I know uploading and downloading here is useless, I wrote it to express how I think the syntax should be used.
Is there a way to do this all on GPU? Or is there another more efficient way to accomplish my goal?