A source device transmits an output format notify message for video data to a sink device before transmitting the video data to the sink device, the output format notify message including a 3D field storing data for identifying whether the video data to be transmitted is two-dimensional video data or three-dimensional video data transmitted using frame packing. In response to this, the sink device identifies a type and a format structure of the video data, and decodes the received video data based on the identified type and format structure of the video data.