Hello I have a problem with this error

Videoio error v4l: property <unknown property="" string=""> (21) When i installed libv4l-dev But each time this error message

thenks

I just changed CV_CAP_PROP AUTO EXPOSURE thank you very much

Ok but it is not static how to make it static

my camera it's logitech c170

I just want to have a static acquisition temp and equal to 60fps

You mean there is no possibility to set this with a change in max temp wait

I tried to put that

cap.set(CV_CAP_PROP_FRAME_WIDTH, 160);
cap.set(CV_CAP_PROP_FRAME_HEIGHT, 120);
cap.set(CV_CAP_PROP_FORMAT, CV_8UC1);
cap.set(CV_CAP_PROP_GAIN, 50); // values range from 0 to 100
cap.set(CV_CAP_PROP_EXPOSURE, 50); //-1 is auto, values range from 0 to 100
cap.set(CV_CAP_PROP_WHITE_BALANCE_RED_V, 50); //values range from 0 to 100, -1 auto whitebalance
cap.set(CV_CAP_PROP_WHITE_BALANCE_BLUE_U, 50); //values range from 0 to 100,  -1 auto whitebalance
cap.set(CV_CAP_PROP_BRIGHTNESS, 85);

But it is always the same problem, when I put my finger in the camera the number of capture begins to slow

Hi everybody, I have a problem with my webcam, has every faith it makes night it becomes slower my code and the following:

    #include "opencv2/opencv.hpp"
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
void main(void)

{

VideoCapture cap;

cap.open(0);

cap.set(CV_CAP_PROP_FRAME_WIDTH, 160*2);
cap.set(CV_CAP_PROP_FRAME_HEIGHT, 120*2);
cap.set(CAP_PROP_FPS,60);
cap.set(CV_CAP_PROP_POS_MSEC, 100);
cap.set(CV_CAP_PROP_BRIGHTNESS, 100);
cap.set(CV_CAP_PROP_CONTRAST, 100);
cap.set(CV_CAP_PROP_SATURATION, 200);
cap.set(CV_CAP_PROP_HUE, 1);
cap.set(CV_CAP_PROP_GAIN, 100);
cap.set(CAP_PROP_AUTOFOCUS, 0);

//cap.set(CV_CAP_PROP_EXPOSURE, CAP_PROP_ISO_SPEED);
while (1)
{
    Mat frame;
    int64 t = getTickCount();
    cap.grab();
    cap.retrieve(frame);
    t = getTickCount() - t;
    printf("Time elapsed: %fms\n", t * 1000 / getTickFrequency());
    cout << cap.get(CAP_PROP_FPS) << endl;
    imshow("frame", frame);

waitKey(timing);
}

}

Hi everybody, I have a problem with my webcam, has every faith it makes night it becomes slower my code and the following:

include "opencv2/opencv.hpp"

include <opencv2 core="" core.hpp="">

include <opencv2 highgui="" highgui.hpp="">

using namespace std; using namespace cv;

int timing = 30;

void main(void) { VideoCapture cap;

cap.open(0);

cap.set(CV_CAP_PROP_FRAME_WIDTH, 160*2);
cap.set(CV_CAP_PROP_FRAME_HEIGHT, 120*2);
cap.set(CAP_PROP_FPS,60);
cap.set(CV_CAP_PROP_POS_MSEC, 100);
cap.set(CV_CAP_PROP_BRIGHTNESS, 100);
cap.set(CV_CAP_PROP_CONTRAST, 100);
cap.set(CV_CAP_PROP_SATURATION, 200);
cap.set(CV_CAP_PROP_HUE, 1);
cap.set(CV_CAP_PROP_GAIN, 100);
cap.set(CAP_PROP_AUTOFOCUS, 0);
//cap.set(CV_CAP_PROP_EXPOSURE, CAP_PROP_ISO_SPEED);
while (1)
{
    Mat frame;
    int64 t = getTickCount();
    cap.grab();
    cap.retrieve(frame);
    t = getTickCount() - t;
    printf("Time elapsed: %fms\n", t * 1000 / getTickFrequency());
    cout << cap.get(CAP_PROP_FPS) << endl;
    imshow("frame", frame);


    waitKey(timing);
}

}