Method and apparatus for quantization and inverse-quantization of picture data

摘要

The quantization information (Q3 Q4 Q5) entered to a shifter 110 is shifted using the quantization quantity (Q1 Q2) as an amount of shifting. The upper three bits of the shifted quantization information are added in an addition unit 112 to a value S1 resulting from conversion by a table 111 of the quantization information (Q1 Q2). The four bits from the addition unit 112 are appended to the lower three bits of the shifted quantization information to reproduce 7-bit quantization characteristics. The picture data may be quantized or inverse-quantized using the quantization characteristics having a wide range and appropriate precision. <IMAGE>