The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT), flat-panel display which includes liquid-crystal displays, or projection displays using fixed picture-element (pixel) arrays. Wikipedia
The Video resolution refers to the aspect ratio of the video. eg. Full HD 1080p = 1920 × 1080 pixels; 720p = 1280x720 pixels; 450p = 800x450 pixels. You should definitely pay attention on it. Do not change the video ratio when embedding the Restreamer player von your website. Always change percentage! Otherwise the image is warped.