OpenCV的 - 让滑块视频播放过程中，以更新其位置 [英] OpenCV - getting the slider to update its position during video playback

问题描述

我拿起学习OpenCV的，并一直在尝试一些code范例/练习。在这个code片段，我想滑块以更新其与每个视频帧变化​​位置，但由于某种原因，它不会工作（图片具有以下code冻结）：

 的#includecv.h
＃包括highgui.hINT g_slider_position = 0;
CvCapture * g_capture = NULL;无效onTrackbarSlide（INT POS）
{
    cvSetCaptureProperty（g_capture，CV_CAP_PROP_POS_FRAMES，POS）
}INT主（INT ARGC，字符** argv的）
{
    cvNamedWindow（汤姆'东经杰里展，CV_WINDOW_AUTOSIZE）;
    g_capture = cvCreateFileCapture（的argv [1]）;
    诠释帧=（INT）cvGetCaptureProperty（
        g_capture，
        CV_CAP_PROP_FRAME_COUNT
        ）;    如果（帧！= 0）
    {
        cvCreateTrackbar（
            位置，
            汤姆'东经杰里秀，
            ＆安培; g_slider_position，
            帧，
            onTrackbarSlide
            ）;
    }    * IplImage结构框架;    而（1）
    {
        帧= cvQueryFrame（g_capture）;
        如果（！帧）
            打破;        cvSetTrackbarPos（
            位置，
            汤姆'东经杰里秀，
            ++ g_slider_position
            ）;        cvShowImage（汤姆'东经杰里展，帧）;
        焦C = cvWaitKey（33）;
        如果（C == 27）
            打破;
    }    cvReleaseCapture（安培; g_capture）;
    cvDestroyWindow（汤姆'东经杰里展）;    返回0;
}
 

任何想法如何让滑块和视频按预期？工作

解决方案

 这是实际工作code//程序添加A更新的TrackBar到视频＃包括LT＆;＆cv.h GT;
＃包括LT＆;＆highgui.h GT;
INT g_slider_position = 0;
CvCapture * video_capture = NULL;无效onTrackbarSlide（INT current_frame）
{
    current_frame = g_slider_position;
    cvSetCaptureProperty（video_capture，CV_CAP_PROP_POS_FRAMES，current_frame）;
}INT主（INT ARGC，字符** argv的）
{
    cvNamedWindow（视频，CV_WINDOW_AUTOSIZE）;
    video_capture = cvCreateFileCapture（Crowdy.avi）;
    INT no_of_frames =（int）的cvGetCaptureProperty（video_capture，CV_CAP_PROP_FRAME_COUNT）;
    如果（no_of_frames！= 0）
    {
        cvCreateTrackbar（滑块，视频，和放大器; g_slider_position，no_of_frames，onTrackbarSlide）;
    }    * IplImage结构框架;    而（1）
    {
        帧= cvQueryFrame（video_capture）;
        如果突破（帧！）;
        cvShowImage（视频，帧）;
        cvSetTrackbarPos（滑块，视频，++ g_slider_position）;
        焦C = cvWaitKey（33）;
        如果（C == 27）破;
    }
    cvReleaseCapture（安培; video_capture）;
    cvDestroyWindow（视频）;    返回（0）;
}
 

I've picked up 'Learning OpenCV' and have been trying some of the code examples/exercises. In this code snippet, I want to get the slider to update its position with each video frame change, but for some reason it won't work (the picture freezes with the following code):

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

int g_slider_position = 0;
CvCapture* g_capture = NULL;

void onTrackbarSlide(int pos)
{
    cvSetCaptureProperty(g_capture, CV_CAP_PROP_POS_FRAMES, pos);
}

int main(int argc, char** argv)
{
    cvNamedWindow("The Tom 'n Jerry Show", CV_WINDOW_AUTOSIZE);
    g_capture = cvCreateFileCapture(argv[1]);
    int frames = (int) cvGetCaptureProperty(
        g_capture, 
        CV_CAP_PROP_FRAME_COUNT
        );

    if (frames != 0)
    {
        cvCreateTrackbar(
            "Position",
            "The Tom 'n Jerry Show",
            &g_slider_position,
            frames,
            onTrackbarSlide
            );
    }

    IplImage* frame;

    while (1)
    {
        frame = cvQueryFrame(g_capture);
        if (!frame) 
            break;

        cvSetTrackbarPos(
            "Position", 
            "The Tom 'n Jerry Show",
            ++g_slider_position
            );

        cvShowImage("The Tom 'n Jerry Show", frame);
        char c = cvWaitKey(33);
        if (c == 27)
            break;
    }

    cvReleaseCapture(&g_capture);
    cvDestroyWindow("The Tom 'n Jerry Show");

    return 0;
}

Any idea how to get the slider and video to work as intended?

解决方案

This is the actual working code



// PROGRAM TO ADD A UPDATING TRACKBAR TO A VIDEO

#include <cv.h>
#include <highgui.h>


int g_slider_position = 0;
CvCapture* video_capture = NULL;

void onTrackbarSlide(int current_frame)
{
    current_frame = g_slider_position;
    cvSetCaptureProperty(video_capture,CV_CAP_PROP_POS_FRAMES,current_frame);
}

int main( int argc, char** argv )
{
    cvNamedWindow( "Video", CV_WINDOW_AUTOSIZE );
    video_capture = cvCreateFileCapture( "Crowdy.avi");
    int no_of_frames = (int) cvGetCaptureProperty(video_capture,CV_CAP_PROP_FRAME_COUNT);
    if( no_of_frames!= 0 ) 
    {
        cvCreateTrackbar("Slider","Video",&g_slider_position,no_of_frames,onTrackbarSlide);
    }

    IplImage* frame;

    while(1) 
    {
        frame = cvQueryFrame( video_capture );
        if( !frame ) break;
        cvShowImage( "Video", frame );
        cvSetTrackbarPos("Slider","Video",++g_slider_position);
        char c = cvWaitKey(33);
        if( c == 27 ) break;
    }
    cvReleaseCapture( &video_capture );
    cvDestroyWindow( "Video" );

    return(0);
}

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