Getting all available frame size from capture device with OpenCV

Question

I'm using Open CV 2.4.6 with C++ (with Python sometimes too but it is irrelevant). I would like to know if there is a simple way to get all the available frame sizes from a capture device?

For example, my webcam can provide 640x480, 320x240 and 160x120. Suppose that I don't know about these frame sizes a priori... Is it possible to get a vector or an iterator, or something like this that could give me these values?

In other words, I don't want to get the current frame size (which is easy to obtain) but the sizes I could set the device to.

Thanks!

Answer 1

When you retrieve a frame from a camera, it is the maximum size that that camera can give. If you want a smaller image, you have to specify it when you get the image, and opencv will resize it for you. A normal camera has one sensor of one size, and it sends one kind of image to the computer. What opencv does with it thereafter is up to you to specify.