| 摘要 |
<p>PURPOSE:To always execute efficient variable length coding under various conditions. CONSTITUTION:A pattern received by a run-level pattern conversion section 9 is converted into a run-level pattern representing number of patterns whose quantization level is 0 and succeeding number of values other than 0 as one set and information (EOB) representing remaining quantization levels are all zero. Then a counter 12 counts total number of generated patterns and a counter 13 counts number of EOB information sets for each block and the results are respectively stored in memories 14, 15. A code table decision section 16 calculates a ratio e=m/n of number of times of EOB information sets (m) to total generated pattern number (n) of plural blocks coded already in the vicinity of a coding object block and selects any of coding tables 1-8 generated by a pattern generation probability distribution according to the predetermined selection rule based on the ratio. A variable length coding section 10 uses the selected code table to apply variable length coding to a pattern from the pattern conversion section 9.</p> |
