如何使用cv2获取视频的持续时间

Question

我只能CAP_PROP_FRAME_COUNT使用CV2 获得帧数.

但是,我找不到参数来使用cv2获取视频的持续时间.

怎么做？

非常感谢你.

Answer 1

cv2不是为了探索视频元数据而设计的,因此VideoCapture没有API直接检索它.

您可以改为"测量"流的长度:寻找到最后,然后获取时间戳:

>>> v=cv2.VideoCapture('sample.avi')
>>> v.set(cv2.CAP_PROP_POS_AVI_RATIO,1)
True
>>> v.get(cv2.CAP_PROP_POS_MSEC)
213400.0

检查显示这设置了最后一帧之后(而不是之前)的点,因此时间戳确实是流的确切总长度:

>>> v.get(cv2.CAP_PROP_POS_FRAMES)
5335.0
>>>> v.get(cv2.CAP_PROP_FRAME_COUNT)
5335.0

>>> v.set(cv2.CAP_PROP_POS_AVI_RATIO,0)
>>> v.get(cv2.CAP_PROP_POS_FRAMES)
0.0        # the 1st frame is frame 0, not 1, so "5335" means after the last frame

Answer 2

在OpenCV 3中，解决方案是：

import cv2

cap = cv2.VideoCapture("./video.mp4")
fps = cap.get(cv2.CAP_PROP_FPS)      # OpenCV2 version 2 used "CV_CAP_PROP_FPS"
frame_count = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
duration = frame_count/fps

print('fps = ' + str(fps))
print('number of frames = ' + str(frame_count))
print('duration (S) = ' + str(duration))
minutes = int(duration/60)
seconds = duration%60
print('duration (M:S) = ' + str(minutes) + ':' + str(seconds))

cap.release()

Answer 3

捕获视频并输出持续时间为秒

vidcapture = cv2.VideoCapture('myvideo.mp4')
fps = vidcapture.get(cv2.CAP_PROP_FPS)
totalNoFrames = vidcapture.get(cv2.CAP_PROP_FRAME_COUNT);
durationInSeconds = float(totalNoFrames) / float(fps)

print("durationInSeconds: ",durationInSeconds,"s")