INFORMATION SIGNAL ENCODING DEVICE AND METHOD AND INFORMATION SIGNAL DECODING METHOD

摘要

PROBLEM TO BE SOLVED: To further reduce the quantity of data to be sent when the residual signals produced via the estimated encoding are quantized and transmitted. SOLUTION: The residual signals which are produced when the input digital information signals undergo the estimated encoding are turned into blocks, and the maximum value MAX and the minimum value MIN of every block are detected. A mode decision circuit 5 decides a quantization mode based on a fact whether the level range of both value MAX and MIN covers 0. Then a mode signal MODE is produced to instruct a mode. If the level range covers 0, a 1st quantization mode is selected. Then a 2nd quantization mode is selected if the level range does not cover 0. A quantization circuit 6 performs the normal quantization in the 1st quantization mode and then performs the code conversion to decrease the number of quantization output bits in the 2nd quantization mode.