ESP32-CAM stream into OpenCV / C++ / cURL / libcurl

Projects Programming
1

Hello, I am making project in which I used ESP32-CAM to create a Wi-Fi network that I connect to with my laptop. So far I have been using method of downloading images using libcurl inside my application on laptop.

And it works but I have found that OpenCV function "cv::VideoCapture" can stream from URLs so I have tried passing URL but it didn't work.

Basically I have been using "192.168.4.1/capture" as an URL but I would like to try "192.168.4.1:81/stream" if it wouldn't make my video on laptop run more "smoothly".

Code inside ESP32-CAM is from this nice tutorial:

Code inside my C++ app is something like this:

cv::Mat curlImg(const char* img_url, int timeout = 10)  //  Retrieves the image as cv::Mat data type
{
    std::vector<uchar> stream;
    CURL* curl = curl_easy_init();
    curl_easy_setopt(curl, CURLOPT_URL, img_url); //the img url
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data); // pass the writefunction
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &stream); // pass the stream ptr to the writefunction
    curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout); // timeout if curl_easy hangs, 
    CURLcode res = curl_easy_perform(curl); // start curl
    curl_easy_cleanup(curl); // cleanup
    return cv::imdecode(stream, -1); // 'keep-as-is'
}


int main()
{
    //cv::VideoCapture cam("http://192.168.4.1:81/stream"); I wanted to use this, but my program would just freeze


    while (loop)
    {
        start = clock();
        cv::Mat frame;
        frame = curlImg("http://192.168.4.1/capture");
        //bool b = cam.read(frame);

        cv::imshow("Window", frame);

        int key = cv::waitKey(1);
        if (key == 27)
            break;


        endTime = clock();
        int deltaTime = difftime(endTime, start);
        std::cout << deltaTime << "\n";
    }

    return 0;
}

Thanks in advance for any help.

2

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