shm-demo/receiver.cpp

#include <iostream>
#include <opencv2/opencv.hpp>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>

int main() {
    // 打开共享内存
    int shmFd = shm_open("/video_shm", O_RDWR, 0666);
    if (shmFd == -1) {
        std::cerr << "Failed to open shared memory" << std::endl;
        return 1;
    }
    void* sharedMemory = mmap(NULL, sizeof(int) * 3 + sizeof(double), PROT_READ | PROT_WRITE, MAP_SHARED, shmFd, 0);
    if (sharedMemory == MAP_FAILED) {
        std::cerr << "Failed to map shared memory" << std::endl;
        return 1;
    }

    // 获取共享内存指针
    char* dataPtr = static_cast<char*>(sharedMemory);

    // 创建窗口用于显示视频
    cv::namedWindow("Received Video", cv::WINDOW_NORMAL);

    // 接收并实时播放视频帧
    while (true) {
        // 读取图像尺寸
        int width = *reinterpret_cast<int*>(dataPtr);
        dataPtr += sizeof(int);
        int height = *reinterpret_cast<int*>(dataPtr);
        dataPtr += sizeof(int);
        int type = *reinterpret_cast<int*>(dataPtr);
        dataPtr += sizeof(int);

        // 计算图像数据的大小
        size_t imageDataSize = width * height * CV_ELEM_SIZE(type);

        // 创建图像矩阵
        cv::Mat frame(height, width, type, reinterpret_cast<void*>(dataPtr));
        dataPtr += imageDataSize;

        // 读取帧率信息
        double fps = *reinterpret_cast<double*>(dataPtr);
        dataPtr += sizeof(double);

        // 显示图像
        cv::imshow("Received Video", frame);

        // 打印帧率
        std::cout << "Received FPS: " << fps << std::endl;

        // 按下 ESC 键退出循环
        if (cv::waitKey(1) == 27)
            break;
    }

    // 关闭共享内存
    munmap(sharedMemory, sizeof(int) * 3 + sizeof(double));
    close(shmFd);

    return 0;
}