ARITHMETIC ENCODING DEVICE AND ARITHMETIC DECODING DEVICE

摘要

PROBLEM TO BE SOLVED: To perform a high-speed processing without impairing compressibility. SOLUTION: The predicted probability of a pixel under consideration is stored in a predicted probability storage part 302 for the respective plural kinds of the surrounding pixel information of the pixel under consideration and a surrounding pixel information decision part 301 decides the surrounding pixel information based on the surrounding pixel state of the pixel under consideration and selects the predicted probability of the pixel under consideration corresponding to the surrounding pixel information from the predicted probability storage part 302. An arithmetic encoder 303 performs arithmetic encoding based on the predicted probability. Also, a symbol counting part counts the number of times that a predicted symbol value read from a predicted symbol storage part and an actual symbol value match and predicted probability control changes the predicted probability read from the predicted probability storage part based on the number of times of matching.