OpenCV库很强大，不仅能够显示图片，还能解码显示各种格式的视频文件，而且提供的API接口也很多，包括C、C++、Python。下面比较一下分别使用C和C++播放一段视频文件的实现：

C语言实现

$ cat test_video.c
#include <opencv/cv.h>
#include <opencv/highgui.h>
#include <stdio.h>


int main(int argc, char **argv)
{
    CvCapture *cap;
    IplImage *frame;

    cap = cvCaptureFromFile("./kakou.mp4");

    printf("cap = %p\n", cap);
    while ((frame = cvQueryFrame(cap))) {
        //printf("frame = %p\n", frame);
        cvShowImage("MyTest", frame);
        cvWaitKey(33);
    }

    return 0;
}
$ gcc -o test_video test_video.c -lopencv_core  -lopencv_imgproc -lopencv_highgui

C++语言实现

$ cat test_video.cpp
#include <iostream>
#include <opencv/highgui.h>

using namespace std;
using namespace cv;
int main(void){

    //打开视频文件
    VideoCapture capture("./kakou.mp4");

    //isOpen判断视频是否打开成功
    if(!capture.isOpened())
    {
        cout<<"Movie open Error"<<endl;
        return -1;
    }
    //获取视频帧频
    double rate=capture.get(CV_CAP_PROP_FPS);
    cout<<"帧率为:"<<" "<<rate<<endl;
    cout<<"总帧数为:"<<" "<<capture.get(CV_CAP_PROP_FRAME_COUNT)<<endl;//输出帧总数
    Mat frame;
    namedWindow("Movie Player");

    double position=0.0;
    //设置播放到哪一帧，这里设置为第0帧
    capture.set(CV_CAP_PROP_POS_FRAMES,position);
    while(1)
    {
        //读取视频帧
        if(!capture.read(frame))
            break;

        imshow("Movie Player",frame);
        //获取按键值
        char c=waitKey(33);
        if(c==27)
            break;
    }
    capture.release();
    destroyWindow("Movie Player");
    return 0;
}
$g++ -o test_video test_video.cpp -lopencv_core  -lopencv_imgproc -lopencv_highgui

来一个效果图：