| 摘要 |
<p>PURPOSE:To generate coded data while suppressing deterioration in image quality with simple configuration by generating difference image data between adjacent patterns based on an orthogonal transformation coefficient and coding the generated image data. CONSTITUTION:Coded data of a frame number N and a succeeding frame number (N+1) are given to variable length decoding circuits 10, 11, in which the data are decoded and inverse quantization circuits 12, 13 restore a DCT coefficient value. Then a subtractor circuit 14 subtracts a DCT coefficient value of a frame #N from a DCT coefficient value of a frame #(N+1) to generate a DCT coefficient value being an inter-frame difference. The difference DCT coefficient value obtained by the circuit 14 is re-quantized by a quantization circuit 15 and quantization data are coded by a variable length coding circuit 16. Thus, one set of the variable length decoding circuit and the inverse quantization circuit is enough for the processing unit by storing DCT coefficient data after inverse quantization for one frame in a frame memory or the like.</p> |
