播放声音 C++ linux aplay：设备或资源繁忙

Question

每当使用 C++ (LINUX) 中的 opencv 在相机中检测到人脸时，我都会尝试播放一个小音频 (.wav) 文件。

    #include "opencv2/objdetect.hpp"
    #include "opencv2/videoio.hpp"
    #include "opencv2/highgui.hpp"
    #include "opencv2/imgproc.hpp"
    
    #include <iostream>
    #include <stdio.h>
    
    using namespace std;
    using namespace cv;
    
    /** Global variables */
    String faceCascadePath;
    CascadeClassifier faceCascade;
    
    void detectFaceOpenCVHaar(CascadeClassifier faceCascade, Mat &frameOpenCVHaar, int inHeight=300, int inWidth=0)
    {
        int frameHeight = frameOpenCVHaar.rows;
        int frameWidth = frameOpenCVHaar.cols;
        if (!inWidth)
            inWidth = (int)((frameWidth / (float)frameHeight) * inHeight);
    
        float scaleHeight = frameHeight / (float)inHeight;
        float scaleWidth = frameWidth / (float)inWidth;
    
        Mat frameOpenCVHaarSmall, frameGray;
        resize(frameOpenCVHaar, frameOpenCVHaarSmall, Size(inWidth, inHeight));
        cvtColor(frameOpenCVHaarSmall, frameGray, COLOR_BGR2GRAY);
    
        std::vector<Rect> faces;
        faceCascade.detectMultiScale(frameGray, faces);
    
        for ( size_t i = 0; i < faces.size(); i++ )
        {
          int x1 = (int)(faces[i].x * scaleWidth);
          int y1 = (int)(faces[i].y * scaleHeight);
          int x2 = (int)((faces[i].x + faces[i].width) * scaleWidth);
          int y2 = (int)((faces[i].y + faces[i].height) * scaleHeight);
          rectangle(frameOpenCVHaar, Point(x1, y1), Point(x2, y2), Scalar(0,255,0), (int)(frameHeight/150.0), 4);
         
   //// ==== AUDIO PLAY CODE BEGINS ======= ////
          string str1 = "aplay ";
          str1 = str1 + " out.wav" + " & ";
          const char *command = str1.c_str();
          system(command);
   //// ==== AUDIO CODE ENDS ======== /////
    
        }
    }
    
    
    int main( int argc, const char** argv )
    {
        faceCascadePath = "haarcascade_frontalface_default.xml";
        if(!faceCascade.load(faceCascadePath))
        {
            printf("--(!)Error loading face cascade\n");
            return -1;
        }
    
        VideoCapture source;
        if (argc == 1)
            source.open(0, CAP_V4L);
        else
            source.open(argv[1]);  Mat frame;
    
        double tt_opencvHaar = 0;
        double fpsOpencvHaar = 0;
    
        while (true)
        {
            source >> frame;
            if (frame.empty())
                break;
    
            double t = cv::getTickCount();
            detectFaceOpenCVHaar(faceCascade, frame);
            tt_opencvHaar = ((double)cv::getTickCount() - t)/cv::getTickFrequency();
            fpsOpencvHaar = 1/tt_opencvHaar;
             
            putText(frame, format("OpenCV HAAR ; FPS = %.2f",fpsOpencvHaar), Point(10, 50), FONT_HERSHEY_SIMPLEX, 1.3, Scalar(0, 0, 255), 4);
    
            imshow("OpenCV - HAAR Face Detection", frame);
    
            int k = waitKey(5);
            if(k == 27)
            {
                destroyAllWindows();
                break;
            }
        }
    }

现在发生的情况是，每当一个人在镜头前停留更长时间时，相机就会不断检测面部，并且声音文件会不断尝试播放，但由于设备已经忙于播放声音，因此在控制台上会出现错误。当然我可以听到警报，但是如何在警报已经播放时停止同时播放警报，或者如何让他们在声音文件完成之前等待。 这种对声音文件播放的持续调用也会减慢代码的速度。如何修复此错误并优化音频播放使其不会对 cpu 造成压力？

错误：-

Playing WAVE 'out.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Playing WAVE 'out.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

aplay : audio open error: Device or resource busy

我需要帮助：使声音播放流畅且不占用 CPU。人脸检测以大约 30fps 的速度发生，因此对于每一帧，声音都在尝试播放，这是不可能的，并且可能会减慢代码速度。

Answer 1

也许试试这个代码：

if (face_recognized) {
string str1= "aplay" ;
str1 = str1 + "-Dhw:0,3 alarm.wav" + " & ";
const char *command = str1.c_str();
system(command)

while (face_recognized)
{
face_recognized = check_if_face_is_recognised(); // replace with function that checks if face is recognised
}
}

不确定这是否可行，因为我没有 linux，但我希望它有用。