Method for transmitting and receiving graphic data between an image display apparatus and an external apparatus, and information frame structure including information on the graphic data

An information frame structure including information on at least one graphic data which is transmitted to an image display apparatus beforehand prior to transmission of the at least one graphic data from an external apparatus, in which the external apparatus transmits an image data and the at least one graphic data for a graphic image to be displayed by overlapping on an image corresponding to the image data, comprising:

• a “TypeCode” field indicating an information data;
• a “datalength” field including information on a length of the information data;
• and
• a “Frame ID” field in which identifiers (e.g., frame IDs) of the at least one graphic data to be transmitted following transmission of the information data are written.

A method for transmitting and receiving graphic data in an external apparatus, comprising:

• receiving a transmission request for at least one graphic data of an graphic image to be displayed by overlapping on a predetermined image from an image display apparatus on which the predetermined image is being displayed;
• outputting, in response to the request, an information data including information on the at least one graphic data to the image display apparatus;
• outputting the at least one graphic data to the image display apparatus, when a transmission request for the at least one graphic data is again received from the image display apparatus following output of the information data;
• and
• outputting information data including information on the subsequent graphic data to the image display apparatus when a transmission request for a subsequent graphic data of the at least one graphic data following output of the information data is received from the image display apparatus.