Abstract: A picture ratio controlling apparatus and method by which a user controls a picture ratio of a video signal provided to a video display device so as to easily control the picture ratio of the video signal displayed on the video display device. The picture ratio controlling apparatus includes a video display device displaying a video, and a system controller determining at least one selectable picture ratio mode based on information of the picture ratio of a source video to be provided to the video display device and the information of the picture ratio that can be supported by the video display device, and controls the picture ratio of the source video provided to the video display device, when a user requests a picture ratio selection. Accordingly, the user can control the picture ratio of a video displayed on the video display device by simply manipulating a key.

Abstract: The transport decoder is disclosed including: a demultiplexer for demultiplexing an input transport stream, to output PID streams desired by a user in the form of transport stream, and outputting the transport stream other than the PID stream according to an output control signal selected by the user; a storage for storing the transport stream output from the demultiplexer; second, third and fourth decoders for decoding video data, audio data and additional data according to a select control signal selected by the suer, respectively; a first decoder for decoding the transport stream, to decode the stream other than the currently being decoded video data stream, audio data stream and additional data stream according to a selection of the user, and to transmit it; and control means for providing the output control signal.