Several instances of the element provide various mapping of media. Element to multiple screensbasedon available combinations. For example.One element represents mapping of all multimedia element to one screen while another element represents mapping of these element into two screens. Methods for selection of specific elements are not specified in MMT specifications. element allows various methods for specifying time related information needed for synchronization. It can be used to specify absolute start time or end time of media element by using UTC. If also allows relative representation of start time or end time of media elements by referencing other media elements or specific events defined in the same HTML5 document.