Method of scaling subpicture data and related apparatus

A video processing circuit, comprising:

• an input for receiving a video data stream and a subpicture data stream;
• a decoding module for pre-parsing the subpicture data stream to obtain line information of subpicture data, the subpicture data containing both top field pixel data and bottom field pixel data;
• a subpicture scaling module for calculating the number of lines contained in the top field pixel data and the bottom field pixel data from the pre-parsed line information, interlacing the top field pixel data and the bottom field pixel data, scaling the top and bottom field pixel data together in interlaced form for adjusting the number of lines contained in the top field pixel data and the bottom field pixel data, and separating the scaled pixel data into updated top field pixel data and updated bottom field pixel data;
• and
• a memory for separately storing the updated top field pixel data and the updated bottom field pixel data in a memory.

A digital versatile disc (DVD) system comprising:

• interface logic for receiving audio, video, and subpicture data streams;
• audio/video (AV) decoding circuitry for decoding the received audio and video data streams;
• and
• subpicture decoding circuitry for decoding the received subpicture data stream, the subpicture decoding circuitry comprising:
• a decoding module for pre-parsing the subpicture data stream to obtain line information of subpicture data, the subpicture data containing both top field pixel data and bottom field pixel data;
• a subpicture scaling module for calculating the number of lines contained in the top field pixel data and the bottom field pixel data from the pre-parsed line information, interlacing the top field pixel data and the bottom field pixel data, scaling the top and bottom field pixel data together in interlaced form for adjusting the number of lines contained in the top field pixel data and the bottom field pixel data, and separating the scaled pixel data into updated top field pixel data and updated bottom field pixel data;
• and
• a memory for separately storing the updated top field pixel data and the updated bottom field pixel data in a memory.