Electronics and Telecommunications Research Institute

Sang-Beom Kim

Jang-Sik Choi

Ki-Hyun Kim

Seung-Ku Hwang

Byoung-Ki Min

Kyung-Joon Song

A discrete cosine transform circuit for processing an 8.times.8 block and two 4.times.8 blocks, comprising a first shuffle circuit for performing a first one-dimensional discrete cosine transform, a second shuffle circuit for performing a second one-dimensional discrete cosine transform, a first multiplexing circuit for selecting inputs to input terminals of adders/subtracters in the second shuffle circuit according to an input block size, ROMs for storing a data table therein to support all cosine matrices to perform a matrix multiplication operation based on the input block size, and a second multiplexing circuit for selecting a desired one of outputs from the ROMs according to the input block size. Therefore, according to the present invention, common and different parts for the process of two different block sizes are all implemented on a single circuit and controlled to process forward and inverse discrete cosine transforms.

Discrete cosine transform circuit for processing an 8.times.8 block and

Disclosed is a quantization/inverse quantization circuit including a differential pulse code modulator (DPCM). Video CODEC standards (i.e., JPEG, H.261, H.263, MPEG-1, and MPEG-2) include various functions for an image compression and an image reconstruction. The conventional quantization/inverse quantization circuit has been designed to be fit for only one desired standard, so that the quantization/inverse quantization circuit used for one standard cannot be directly used for another standard. Accordingly, in relation to a difference between standards and required function therebetween in order to use the present invention in all video CODEC standards, the present invention discloses a quantization/inverse quantization circuit which can support all modes (i.e., a quantization mode in coding, an inverse quantization mode in decoding, and a reconstruction mode) by employing one quantization circuit as a quantization/inverse quantization circuit which can be used in all video CODEC standards.

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Seo-ku, South Korea

Sang-Beom Kim