opencv做的简单播放器

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <string>
#include <iostream>
#include <fstream>

using namespace std;

int g_slider_position = 0;
int g_run = 1, g_dontset = 0;
cv::VideoCapture g_cap;
void onTrackbarSlide(int pos, void*) {
	g_cap.set(cv::CAP_PROP_POS_FRAMES, pos);

	if (!g_dontset)
		g_run = 1;
	g_dontset = 0;
}
int main(int argc, char** argv) {
	std::string s = "Video/2020-06/e0927594e320877035894dc0a435f1b6.mp4";

	g_cap.open(s);//视频读取结构，通过传入字符串

	int frames = (int)g_cap.get(cv::CAP_PROP_FRAME_COUNT);
	int tmpw = (int)g_cap.get(cv::CAP_PROP_FRAME_WIDTH);
	int tmph = (int)g_cap.get(cv::CAP_PROP_FRAME_HEIGHT);

	cout << "Video has" << frames << "frames of dimensions(" << tmpw << "," << tmph << ")." << endl;

	cv::createTrackbar("Position", "Example2_4", &g_slider_position, frames, onTrackbarSlide);

	cv::Mat frame;
	for (;;) {
		if (g_run != 0) {
			g_cap >> frame; if (frame.empty())break;
			int current_pos = (int)g_cap.get(cv::CAP_PROP_POS_FRAMES);
			g_dontset = 1;

			cv::setTrackbarPos("Position", "Example2_4", current_pos);
			cv::imshow("Example2_4", frame);

			g_run -= 1;
		}

		char c = (char)cv::waitKey(10);
		if (c == 's') {
			g_run = 1;  cout << "Singal step, run = " << g_run << endl;
		}
		if (c == 'r') {
			g_run = -1; cout << "Run mode, run = " << g_run << endl;
		}
		if (c == 27)
			break;

	}
	cv::destroyWindow("Example2_4");
	return 0;
}