| 摘要 |
PURPOSE: To suppress deterioration in an image to a degree of deterioration caused at first compression even when companding is repeated by estimating a quantization coefficient used for preceding processing even in the case that it is unknown. CONSTITUTION: In a first recording reproduction processing, a transformation coefficient from a discrete cosine transformation(DCT) circuit 14 is fed to a 1st Q estimate circuit 24. A test matrix of quantization values is supplied to the Q estimate circuit 24 via a test Q bus 30. The Q estimate circuit 24 supplies a Q coefficient identification signal to specify a matrix used for properly compressing video image data depending on applications to a Q selector 28 and a Q lookup table 27 supplies each selected matrix quantization value to a quantization circuit 18. At the first repetition, a transformation coefficient corresponding to new video image data is fed from the DCT circuit 14 to Q estimate circuits 24, 26. When quantization processing is conducted, the Q estimate circuit 26 provides a signal denoting how much quantization is made. |
