Abstract:
A coding/decoding apparatus using DCT(Discrete Cosine Transform) coefficient scanning adaptive according to pixel similarity and a method thereof are provided to enhance the compression rate of intra encoding by applying the most efficient scanning method according to pixel similarity and coding or decoding images. A coding apparatus using DCT coefficient scanning comprises a mode selection part(10), an intra prediction part(20), a DCT and quantization part(30), and an entropy coding part(40). The mode selection part(10) selects the optimum mode for intra prediction. The intra prediction part(20) executes intra prediction for an inputted image, based on the selected mode. The DCT and quantization part(30) executes DCT and quantization for the residual coefficients outputted from the intra prediction part(20). Using a certain scanning mode determined according to the pixel similarity of the residual coefficients, the entropy coding part(40) performs entropy coding for the quantized DCT coefficients.
Abstract:
An apparatus for encoding and decoding by using a converter alternatively according to the correlation of residual coefficients and a method thereof are provided to select a converter with a highest compression rate by perform an RD(Rate-Distortion) cost optimization using DCT(Discrete Cosine Transform) and DST(Discrete Sine Transform) in generating a quantized conversion coefficient through converters and quantizers after prediction between images or within the images in a predetermined size of block, thereby improving the compression rate of an image block. A first converter(31-34) performs the DCT(Discrete Cosine Transform) in a block unit, first quantization, first inverse quantization and IDCT(Interger-approximated Discrete Cosine Inverse Transform) of residual coefficients which are generated after performing prediction between images or within the images. A second converter(35-38) performs the DST(Discrete Sine Transform) in the block unit, second quantization, second inverse quantization, and IDST(Interger-approximated Discrete Sine Inverse Transform) of the residual coefficients. A selection unit(39) performs RD Cost(Rate-Distortion Cost) to select a converter with a high compression rate by block, and a display unit(40) displays converter information selected by the selection unit on a corresponding flag bit in a macro block unit.
Abstract:
Provided is an apparatus and method for encoding and decoding using alternative transform units according to the correlation of residual signals. The video encoding apparatus includes a first transforming unit for performing discrete cosine transform (DCT), first quantization, first inverse quantization, and inverse DCT on a block basis onto residual coefficients generated after intra frame prediction or inter frame prediction; a second transforming unit for performing discrete sine transform (DST), second quantization, second inverse quantization, and inverse DST on a block basis onto the residual coefficients; a selecting unit for selecting one having a high compression rate between the first and second transforming units for each block through performing rate-distortion optimization; and a flag marking unit for recording information about the selected transforming unit at a flag bit provided on a macroblock basis.
Abstract:
The present invention discloses an encoding apparatus using a Discrete Cosine Transform (DCT) scanning, which includes a mode selection means for selecting an optimal mode for intra prediction; an intra prediction means for performing intra prediction onto video inputted based on the mode selected in the mode selection means; a DCT and quantization means for performing DCT and quantization onto residual coefficients of a block outputted from the intra prediction means; and an entropy encoding means for performing entropy encoding onto DCT coefficients acquired from the DCT and quantization by using a scanning mode decided based on pixel similarity of the residual coefficients.
Abstract:
The present invention relates to a method and an apparatus for encoding entropy of image data. The entropy encoding method according to the present invention binarizes coefficients of frequency areas generated by converting a residual block of a current block into frequency areas by applying different binarization methods, and adaptively binarizes coefficients according to the magnitudes of the frequencies of the coefficients by binary arithmetic encoding the binarized coefficients, thereby improving the compression rate of image data compression.
Abstract:
본 발명은 영상 데이터의 엔트로피 부호화 방법 및 장치에 관한 것으로 본 발명에 따른 엔트로피 부호화 방법은 현재 블록의 레지듀얼 블록을 주파수 영역으로 변환한 결과 생성된 주파수 영역의 계수들을 각각 서로 다른 이진화 방법을 적용하여 이진화하고, 이진화된 계수들을 이진 산술 부호화함으로써 계수들의 주파수 고저에 따라 적응적으로 계수들을 이진화할 수 있어 영상 데이터 압축의 압축률이 향상된다.