Python |使用OpenCV以反向模式播放视频-yiteyi-C++库

OpenCV （开放源代码计算机视觉）是一个计算机视觉库，包含对图像或视频执行操作的各种功能。

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OpenCV's application areas include :1) Facial recognition system2) motion tracking3) Artificial neural network4) Deep neural network5) video streaming  etc.

在Python中，可以使用名为 CV2 .Python不随cv2提供，所以用户需要单独安装。

对于Windows：
pip install opencv-python
对于Linux：
sudo apt-get install python-opencv

OpenCv库可用于对视频执行多种操作。让我们尝试使用 CV2 .将视频作为输入，以反向模式播放，方法是将视频逐帧分解，同时将该帧存储在列表中。在获得帧列表后，我们对帧执行迭代。为了在反转模式下播放视频，我们只需要在帧列表中迭代反转。使用列表的反转方法反转列表中帧的顺序。以下是实施情况：

Python3

                         # Python program to play a video                       
                         # in reverse mode using opencv                       
           
                         # import cv2 library                       
                         import                                     cv2                       
           
                         # videoCapture method of cv2 return video object                       
           
                         # Pass absolute address of video file                       
                         cap                                     =                                     cv2.VideoCapture(                                     "video_file_location"                                     )                       
           
                         # read method of video object will return                       
                         # a tuple with 1st element denotes whether                       
                         # the frame was read successfully or not,                       
                         # 2nd element is the actual frame.                       
           
                         # Grab the current frame.                       
                         check , vid                                     =                                     cap.read()                       
           
                         # counter variable for                       
                         # counting frames                       
                         counter                                     =                                     0                       
           
                         # Initialize the value                       
                         # of check variable                       
                         check                                     =                                     True                       
           
                         frame_list                                     =                                     []                       
           
                         # If reached the end of the video                       
                         # then we got False value of check.                       
           
                         # keep looping until we                       
                         # got False value of check.                       
                         while                                     (check                                     =                                     =                                     True                                     ):                       
                                   
                                                 # imwrite method of cv2 saves the                       
                                                 # image to the specified format.                       
                                                 cv2.imwrite(                                     "frame%d.jpg"                                     %                                     counter , vid)                       
                                                 check , vid                                     =                                     cap.read()                       
                                   
                                                 # Add each frame in the list by                       
                                                 # using append method of the List                       
                                                 frame_list.append(vid)                       
                                   
                                                 # increment the counter by 1                       
                                                 counter                                     +                                     =                                     1                       
           
                         # last value in the frame_list is None                       
                         # because when video reaches to the end                       
                         # then false value store in check variable                       
                         # and None value is store in vide variable.                       
           
                         # removing the last value from the                       
                         # frame_list by using pop method of List                       
                         frame_list.pop()                       
           
                         # looping in the List of frames.                       
                         for                                     frame                                     in                                     frame_list:                       
                                   
                                                 # show the frame.                       
                                                 cv2.imshow(                                     "Frame"                                     , frame)                       
                                   
                                                 # waitkey method to stopping the frame                       
                                                 # for some time. q key is presses,                       
                                                 # stop the loop                       
                                                 if                                     cv2.waitKey(                                     25                                     )                                     and                                     0xFF                                     =                                     =                                     ord                                     (                                     "q"                                     ):                       
                                                 break                       
                                   
                         # release method of video                       
                         # object clean the input video                       
                         cap.release()                       
           
                         # close any open windows                       
                         cv2.destroyAllWindows()                       
           
                         # reverse the order of the element                       
                         # present in the list by using                       
                         # reverse method of the List.                       
                         frame_list.reverse()                       
           
                         for                                     frame                                     in                                     frame_list:                       
                                                 cv2.imshow(                                     "Frame"                                     , frame)                       
                                                 if                                     cv2.waitKey(                                     25                                     )                                     and                                     0xFF                                     =                                     =                                     ord                                     (                                     "q"                                     ):                       
                                                 break                       
           
                         cap.release()                       
                         cv2.destroyAllWindows()                       

输出：

图片[1]-Python |使用OpenCV以反向模式播放视频-yiteyi-C++库

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