MOVING PICTURE DATA CODING/DECODING METHOD AND ITS DEVICE

摘要

PURPOSE:To simply revise coding accuracy of a DCT DC coefficient by correcting a coding output from a 1st quantization device with a coding output from a 2nd quantization device. CONSTITUTION:An input picture signal 10 is given to a DCT circuit 11, in which the signal is subject to 8X8 DCT coefficient processing, only a DC coefficient S1 through a DC coefficient selector 12 is subject to linear quantization at a 1st quantization device 13 and a quantization coefficient S2 is inputted to a 1st coder 20. Then the quantization coefficient S2 is inversely quantized by an inverse quantization circuit 14 and a decoding signal S3 is inputted to a DC selector 15. Then a 8X8 DCT coefficient S6 having a property whose AC coefficient is a substantial coefficient and whose DC coefficient is a difference between a substantial DC coefficient and a coefficient subject to inverse quantization of a coefficient outputted from a quantization device 13 by the inverse quantization device 14 is outputted from a differential processing circuit 13. The signal S6 is quantized by a 2nd quantization device 18 and its quantization output S7 is inputted to a 2nd coder 19.