| 摘要 |
PURPOSE: To enable encoding and decoding with a small number of applied code tables by providing an information generation frequency counting part which finds occurrence probability and an adaptive code table generation part, and transmitting images in specific data units after variable length encoding using adaptive code tables. CONSTITUTION: A transmission-side information generation frequency counting part 101 counts the generation frequency of CBPCMs (combination information on the pattern of a color difference block and the mode of a mask block) of a frame which is currently encoded and finds the occurrence probability of each CBPCM from the generation frequency. The adaptive code table generation part 103 generates an optimum adaptive code table 104 from the occurrence probability of each CBPCM by using Hoffman method. A variable length encoding part 102 encodes the CBPCMs of a next frame by using the newly generated code table 104. A reception-side information generation frequency counting part 105, on the other hand, counts the generation frequency of CBPCMs to find the occurrence probability of each CBPCM. An adaptive code table generation part 107 generates an optimum adaptive code table 108, which is used to decode the CBPCMs of the next frame. |
