在OpenCV中，类videoccapture处理摄像头读取视频和抓取帧。通过使用videoccapture中的get(PROPERTY_NAME)方法，你可以找到很多关于你正在播放的视频文件的信息。

如何在OpenCV中找到一个摄像头/网络摄像头的帧率?

在OpenCV中，查找连接的摄像头/网络摄像头的帧率不是直接的。文档说get(CAP_PROP_FPS)或get(CV_CAP_PROP_FPS)给出每秒的帧数。这对视频文件是正确的，但对网络摄像头不是。对于网络摄像头和许多其他连接摄像头，你必须手动计算每秒的帧数。您可以从视频中读取一定数量的帧，并查看计算每秒帧需要花费多少时间。

Python

#!/usr/bin/env pythonimport cv2
import timeif __name__ == '__main__' :# Start default cameravideo = cv2.VideoCapture(0);# Find OpenCV version(major_ver, minor_ver, subminor_ver) = (cv2.__version__).split('.')# With webcam get(CV_CAP_PROP_FPS) does not work.# Let's see for ourselves.if int(major_ver)  < 3 :fps = video.get(cv2.cv.CV_CAP_PROP_FPS)print("Frames per second using video.get(cv2.cv.CV_CAP_PROP_FPS): {0}".format(fps))else :fps = video.get(cv2.CAP_PROP_FPS)print("Frames per second using video.get(cv2.CAP_PROP_FPS) : {0}".format(fps))# Number of frames to capturenum_frames = 120;print("Capturing {0} frames".format(num_frames))# Start timestart = time.time()# Grab a few framesfor i in range(0, num_frames) :ret, frame = video.read()# End timeend = time.time()# Time elapsedseconds = end - startprint ("Time taken : {0} seconds".format(seconds))# Calculate frames per secondfps  = num_frames / secondsprint("Estimated frames per second : {0}".format(fps))# Release videovideo.release()

C++

#include "opencv2/opencv.hpp"
#include <time.h>using namespace cv;
using namespace std;int main(int argc, char** argv)
{// Start default cameraVideoCapture video(0);// With webcam get(CV_CAP_PROP_FPS) does not work.// Let's see for ourselves.// double fps = video.get(CV_CAP_PROP_FPS);// If you do not care about backward compatibility// You can use the following instead for OpenCV 3double fps = video.get(CAP_PROP_FPS);cout << "Frames per second using video.get(CAP_PROP_FPS) : " << fps << endl;// Number of frames to captureint num_frames = 120;// Start and end timestime_t start, end;// Variable for storing video framesMat frame;cout << "Capturing " << num_frames << " frames" << endl ;// Start timetime(&start);// Grab a few framesfor(int i = 0; i < num_frames; i++){video >> frame;}// End Timetime(&end);// Time elapseddouble seconds = difftime (end, start);cout << "Time taken : " << seconds << " seconds" << endl;// Calculate frames per secondfps  = num_frames / seconds;cout << "Estimated frames per second : " << fps << endl;// Release videovideo.release();return 0;
}

如何在OpenCV中找到视频的帧率?

如果你正在读取一个视频文件，你可以简单地使用get方法来获得每秒的帧数。下面的例子展示了使用方法
Python

import cv2
if __name__ == '__main__' :video = cv2.VideoCapture("video.mp4");# Find OpenCV version(major_ver, minor_ver, subminor_ver) = (cv2.__version__).split('.')if int(major_ver)  < 3 :fps = video.get(cv2.cv.CV_CAP_PROP_FPS)print ("Frames per second using video.get(cv2.cv.CV_CAP_PROP_FPS): {0}".format(fps))else :fps = video.get(cv2.CAP_PROP_FPS)print ("Frames per second using video.get(cv2.CAP_PROP_FPS) : {0}".format(fps))video.release()

C++

#include "opencv2/opencv.hpp"using namespace cv;
using namespace std;int main(int argc, char** argv)
{// Open video fileVideoCapture video("video.mp4");// double fps = video.get(CV_CAP_PROP_FPS);// For OpenCV 3, you can also use the followingdouble fps = video.get(CAP_PROP_FPS);cout << "Frames per second using video.get(CAP_PROP_FPS) : " << fps << endl;video.release();return 0; }