Capturing 1080p at 30fps from logitech c920 with openCV 2.4.3

logitech, opencv

Solution

As the author of the post already found the solution but didn't add it as an answer I will put the solution here.

You have to set the codec before you set the wanted resolution:

this->camRef.set(CV_CAP_PROP_FOURCC,CV_FOURCC('M','J','P','G'));
this->camRef.set(CV_CAP_PROP_FRAME_WIDTH, 1920);
this->camRef.set(CV_CAP_PROP_FRAME_HEIGHT, 1080);

Problem

I'm trying to capture the video stream off of my Logitech C920 in OpenCV. With Labview I can access an MJPG stream at 30fps 1080p. In opencv I am limited to either 5fps or 640x480. Here is the code relevant to the camera settings: ``` this->camRef.set(CV_CAP_PROP_FRAME_WIDTH, 1920); this->camRef.set(CV_CAP_PROP_FRAME_HEIGHT, 1080); this->camRef.set(CV_CAP_PROP_FOURCC,CV_FOURCC('M','J','P','G')); ``` These all return 1, yet I get a 5fps stream of 1080p which corresponds to the YUY2 stream. If I add the following line: ``` this->camRef.set(CV_CAP_PROP_FPS, 30); ``` This returns 0. I get a 30 fps stream at 640x480. To me it looks like the MJPG setting isn't be accepted but I don't know what to do or how to fix that. EDIT: The following crashes the program. ``` this->camRef.read(this->image); std::cout<< this->camRef.get(CV_CAP_PROP_FOURCC) << std::endl; std::cout<< this->camRef.set(CV_CAP_PROP_FRAME_WIDTH, config.width) << std::endl; std::cout<< this->camRef.set(CV_CAP_PROP_FRAME_HEIGHT, config.height) << std::endl; std::cout<< this->camRef.set(CV_CAP_PROP_FOURCC,CV_FOURCC('M','J','P','G')) << std::endl; std::cout<< this->camRef.get(CV_CAP_PROP_FOURCC) << std::endl; ``` Then in my run code I have the following: ``` void camera::run() { while(true) { if(this->camRef.read(this->image) == 0) { if(this->capture) { cv::imwrite(fileName,this->image); this->count++; } } msleep(15); } } ``` EDIT2: Solution is to set the fourCC codec before setting camera height and width.

Original source