| 摘要 |
PROBLEM TO BE SOLVED: To properly change the size of an image, including a field mode coding DCT coefficient by rationalizing is part a DCT coefficient through the inverse discrete cosine conversion IDCT processing of a decoder and applying the pixel area correction to an image frame having its changed size. SOLUTION: A variable length decoder 112 generates a constant length bit stream, including a quantization estimated error DCT coefficient which is inputted to an IDCT module as a bit stream S3, consisting of an estimated error DCT coefficient that is quantized into a standard form by an IQ: 113. The IDCT module has an IDCT that is slightly different from a standard matrix and processes a DCT coefficient block by means of a matrix, which is selected so as to vertically shift a sample changed in size by a half pixel with regard to the field mode coding. Then the IDCT module omits the parts related to every block of the DCT coefficient to perform an IDCT operation and generates a bit stream S4, where an image size including a pixel-based estimated error, is reduced. |
