RUN LENGTH CODING METHOD, DECRYPTION METHOD, AND DISC OF BIT MAP DATA

摘要

PROBLEM TO BE SOLVED: To provide a method for optimally coding a subtitle superimposed layer or a sub picture layer for high resolution video such as HDTV.SOLUTION: A run length coding method includes four steps. Namely, the method includes: using a second or third shortest codeword for a sequence shorter and longer than pixels in a predetermined color (transparent), using a shortest codeword for a single pixel having an individual color value, and using a third or fourth shortest codeword for a sequence shorter and longer than the same color value.