无法使用VideoCapture在OpenCV + Python中读取或播放视频

问题描述

import cv2
import numpy as np

cap = cv2.VideoCapture('traffic.avi')

retval, frame = cap.read()

print retval

================ RESTART: J:\Python For DIP\traffic_video.py ================
False
>>>

retval的值始终为False，这意味着该命令无法读取视频.读取帧必须为True.我不知道该怎么办.但是，当我使用默认的网络摄像头时，它会变为True.我尝试了许多视频，并出现了相同的问题.注意:我已经正确安装了ffmpeg.

The Value of retval is always False, which means the video is not read by the command. It must be True to read frames. I don't know what to do. However when I use my default webcam it turns to be True. I tried many videos and the same problem appears. Note: I have installed the ffmpeg correctly.

注意:这不是完整的代码，在这一步中，我仅验证cap.read()是True还是False

Note: This is not the full code, in this step I am only validating cap.read() either True or False

推荐答案

此方法保证100％

首先检查您的OpenCV版本，例如2.4.11.您可以通过在Python Shell中键入以下命令来进行检查:

first of all check your version of OpenCV, say for instance 2.4.11. you can check it by typing the following commands in your Python Shell:

>>> from cv2 import __version__
>>> __version__
'2.4.11'
>>>

然后转到C:\opencv\build\x86\vc12\bin并复制opencv_ffmpeg2411.dll.最后，转到Python ex的根目录:C:\Python27并将opencv_ffmpeg2411.dll粘贴到其中

Then go to C:\opencv\build\x86\vc12\bin and copy opencv_ffmpeg2411.dll.Finally go to root directory of Python ex: C:\Python27 and paste opencv_ffmpeg2411.dll in it

之后，创建一个新的Python文件并复制此代码并将其粘贴，以加载您自己的视频

After that create a new Python file and copy this code and paste it loading your own video

import numpy as np
import cv2

# Capture video from file
cap = cv2.VideoCapture('your video')

while True:

    ret, frame = cap.read()

    if ret == True:

        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        cv2.imshow('frame',gray)


        if cv2.waitKey(30) & 0xFF == ord('q'):
            break

    else:
        break

cap.release()
cv2.destroyAllWindows()

例如，您将有一个输出视频，例如:结果

you will have an output video for example like this:Result

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