While the following element will be displayed correctly

Camera {
    width: 200
    height: 200
}

Neither of the following will be displayed at all:

Camera {
    width: 200
}

Camera {
    height: 200
}

Note that omitting either width or height from a Video element does not cause it to disappear - in that case, the missing property is derived from the provided one using the native size of the video clip.