A method of transmitting broadcast data by a broadcast receiver includes connecting the broadcast receiver with a companion device; receiving a request for Electronic Service Guide (ESG) data from the companion device; and transmitting the broadcast data including partial or full ESG information of the ESG data to the companion device based on a type of the request. The ESG data includes a content fragment including an extension element including a component element, and the component element including at least one of a video component element describing a role of a video component, an audio component element describing a role of an audio component, a closed caption component element describing a role of a closed caption component, or an application component element describing a role of an application component, and a capability element for the at least one of the video component or the audio component.