在OpenCV中播放视频

问题描述

我是OpenCV的初学者，我想在OpenCV中播放视频。我做了一个代码，但它只显示一个图像。
我使用OpenCV 2.1和Visual Studio 2008.
我真的很感激，如果有人指导我在哪里我会错了。
这是我的粘贴代码：

I am a beginner to OpenCV and I wish to play a video in OpenCV. I've made a code but it's displaying a single image only.I am using OpenCV 2.1 and Visual Studio 2008.I would really appreciate it if someone guided me where am I going wrong.Here is my pasted code:

#include "stdafx.h"
#include "cv.h"
#include "highgui.h"

int main()
{
CvCapture* capture = cvCaptureFromAVI("C:/OpenCV2.1/samples/c/tree.avi");
IplImage* img = 0;
if(!cvGrabFrame(capture)){              // capture a frame
printf("Could not grab a frame\n\7");
exit(0);}
cvQueryFrame(capture); // this call is necessary to get correct
                   // capture properties
int frameH    = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT);
int frameW    = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH);
int fps       = (int) cvGetCaptureProperty(capture, CV_CAP_PROP_FPS);
int numFrames = (int) cvGetCaptureProperty(capture,  CV_CAP_PROP_FRAME_COUNT);
///numFrames=total number of frames



printf("Number of rows %d\n",frameH);
printf("Number of columns %d\n",frameW,"\n");
printf("frames per second %d\n",fps,"\n");
printf("Number of frames %d\n",numFrames,"\n");

for(int i=0;i<numFrames;i++)
{
IplImage* img = 0;
img=cvRetrieveFrame(capture);
cvNamedWindow( "img" );
cvShowImage("img", img);

}
cvWaitKey(0);
cvDestroyWindow( "img" );
cvReleaseImage( &img );
cvReleaseCapture(&capture);


return 0;
}

推荐答案

c $ c> cvQueryFrame 而不是 cvRetrieveFrame 。正如@Chipmunk指出的，你必须在 cvShowImage 后添加延迟。

You have to use cvQueryFrame instead of cvRetrieveFrame. Also as pointed out by @Chipmunk, you have to add a delay after cvShowImage.

cvNamedWindow( "img" );
for(int i=0;i<numFrames;i++)
{
   IplImage* img = cvQueryFrame(capture);
   cvShowImage("img", img);
   cvWaitKey(10);
}

以下是使用OpenCV播放视频的完整方法：

Here is the complete method to play a video using OpenCV:

int main()
{
    CvCapture* capture = cvCreateFileCapture("C:/OpenCV2.1/samples/c/tree.avi");

    IplImage* frame = NULL;

    if(!capture)
    {
        printf("Video Not Opened\n");
        return -1;
    }

    int width = (int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_WIDTH);
    int height = (int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_HEIGHT);
    double fps = cvGetCaptureProperty(capture, CV_CAP_PROP_FPS);
    int frame_count = (int)cvGetCaptureProperty(capture,  CV_CAP_PROP_FRAME_COUNT);

    printf("Video Size = %d x %d\n",width,height);
    printf("FPS = %f\nTotal Frames = %d\n",fps,frame_count);

    while(1)
    {
        frame = cvQueryFrame(capture);

        if(!frame)
        {
            printf("Capture Finished\n");
            break;
        }

        cvShowImage("video",frame);
        cvWaitKey(10);
    }

    cvReleaseCapture(&capture);
    return 0;
}

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