| 摘要 |
<p>PURPOSE:To control code quantity through only offset control of a quantization section by allowing an offset processing section provided to the post-stage of an arithmetic section to add/subtract an offset to/from prescribed quantization data generated by the arithmetic section based on the setting of rough or accurate degree of quantization. CONSTITUTION:A digital image signal 1 is given to a DCT processing section 2 in which the signal is converted into DCT coefficient data 3 representing power distribution for each of divided areas. The data 3 are quantized by a quantization section 4, quantized data 5 are given to a variable length coding section 6, from which variable length code data 7 are outputted. The data 7 are fed to a transmission line via a buffer 8. Furthermore, a control section 11 detects the storage code quantity in the buffer 8 and generates a quantization parameter 12, which is provided as an output to the quantization section 4. On the other hand, an offset matrix section 21 of the quantization section 4 selects data corresponding to matrix data based on the value of a quantization parameter 12 and provides the output to an adder 16 as offset data 23, which are added to the quantization data.</p> |
