RTSP Camera Resizing

Is there any reason when you use  a RTSP camera, and make the camera picture smaller then the stream it just crops the stream, instead of resizing it to fit inside the window?    

I ask, because when you view streams on a PC, you are able to scale up or down the video to what ever size you want.  Yes it will effect quality I know that.   But it would be nice to get the image to fit inside your display page perfectly without loosing any of the FOV.