Python |使用 OpenCV 以反向模式播放视频
原文:https://www . geesforgeks . org/python-play-video-reverse-mode-use-opencv/
OpenCV (开源计算机视觉)是一个计算机视觉库，包含对图像或视频进行操作的各种功能。
OpenCV's application areas include :
1) Facial recognition system
2) motion tracking
3) Artificial neural network
4) Deep neural network
5) video streaming etc.
在 Python 中，可以使用名为 CV2 的 OpenCV 库。Python 没有附带 cv2，所以用户需要单独安装。
对于窗口:
py pip install opencv-python对于 Linux:
py sudo apt-get install python-opencv
OpenCv 库可以用来对视频进行多种操作。让我们尝试使用 CV2 做一些有趣的事情。将视频作为输入，通过将视频逐帧分解并同时将该帧存储在列表中，以反向模式播放。在获得帧列表后，我们对帧执行迭代。对于以反向模式播放视频，我们只需要在帧列表中反向迭代。使用列表的反转方法反转列表中帧的顺序。 下面是实现:
Python 3
# 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:
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