CODEWITHSUNDEEP
pythonopencvvideo-processing
Josh Katz
Josh Katz

Reputation: 11

how to save a video although i kill the process

i am doing infinite loop to save a video , when i kill the process the file of the video don't open , although the size of the video is very big and this tell me that he is saving the file , but for some reason he can't open it, the release is out of the loop . i would be happy to get solution to this problem thanks

    while True:
        frame, frame_id, time_video = next(self.distributor_frame)
        if frame is not None:
            self.out.write(frame)
        else:
            break

    self.out.release()

Upvotes: 0

Views: 603

Answers (2)

Haru Kaeru
Haru Kaeru

Reputation: 146

If you are working with classes, make sure you implement the __del__ method to properly release the video when the garbage collector deletes your object.

class MyClass:

    def __init__(self, save_output_at:str, window_size_hw:tuple[int, int], save_output_fps:int):
        self.out = cv2.VideoWriter(filename=save_output_at,
                                            fourcc=cv2.VideoWriter_fourcc(*'mp4v'),
                                            frameSize=window_size_hw[::-1],
                                            fps=save_output_fps)
    # [Your write bucles...]

    def close(self):
        """
        Release the video_writer.
        """
        if self.out.isOpened():
            self.out.release()
  
    def __del__(self):
        """
        Destructor.
        """
        self.close()

Upvotes: 0

alkasm
alkasm

Reputation: 23042

If you just want to be able to CTRLC out of the program, you can catch Python's built-in KeyboardInterrupt exception and then continue to close the resource.

try:
    while True:
        frame, frame_id, time_video = next(self.distributor_frame)
        if frame is not None:
            self.out.write(frame)
        else:
            break
except KeyboardInterrupt:
    print('Stopped by keyboard interrupt')
self.out.release()

Normally, if you just send a SIGINT (CTRLC) to stop the script, it will raise an exception in Python, and this exception will cut the program. However, you can intercept this signal with except KeyboardInterrupt and just simply do nothing, i.e., pass or print some message (like I did) or whatever you like. But since we caught the exception and aren't raising it again, the program doesn't end from the interrupt while inside that block.

Alternatively, subclass (or create a class that includes) the VideoWriter and give it a context manager---then even if you get an exception, the resource will be closed. This answer has some good discussion about how to create a context manager yourself.

Upvotes: 2

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