Abstract: A packet transmission apparatus for downloading a program is provided. A packet processor reads a packet from a data buffer and a program tag extractor extracts information from a tag in the packet, which indicates a location where a program is stored. A downloader downloads an individual program from the location and stores the program in a program storage. A program switch controls a program executor to execute a preliminary program while the individual program is being downloaded. When the download is completed, the program switch controls the program executor to switch over to the individual program. The packet executor executes the individual program and controls the packet transmission.

Abstract: A full-scene storage portion stores full-scene BIFS data and if a BIFS command other than Scene Replace is received from an encoder a full-scene composition portion composites the full-scene BIFS data stored in the full-scene storage portion and the BIFS command together to generate new full-scene BIFS data and update the full-scene BIFS data stored in the full-scene storage portion and periodically or if a reception system issues a transmission request the full-scene BIFS data stored in the full-scene storage portion is transmitted to the reception system. Thus a scene can be displayed with high quality.