| 摘要 |
PURPOSE:To improve predictive accuracy for the amount of generated codes concerning each block by adjusting the code amount by the zero replacement of a coefficient when or before executing run length encoding. CONSTITUTION:A reducing amount adjusting part 100 is composed of a code amount calculation part 110 by evaluation values, reducing code amount calculation part 120, evaluation value setting part 36 and coefficient zero replacement part 38. A data memory 40 is provided to execute the prescribed preprocessing of reduction to the sequence of quantized coefficients after calculating the reducing amount at the reducing amount calculation part 100. An evaluation value is set to each coefficient after DCT(discrete cosine transformation) is executed, a prescribed threshold value is decided according to the reduced code amount and at the coefficient zero replacement part 38, the coefficient having the evaluation value lower than the threshold value is replaced with zero. By executing the run length encoding of 'zero' to this replacement, data are compressed and encoded. |
