• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.3A
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• pp.211-220
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• 2002

In this paper, we propose an efficient algorithm to compress simple computer cell animation at very low bit rate. The structure of proposed algorithm consists of intra frame coding and inter frame coding. In inter frame coding, animation is encoded by color quantization using a palette, rearrangement of index, ADPCM used in JPEG-LS, mapping, classification, and entropy coding. In interframe coding, classifying the characteristics of motion, animation is encoded by block based motion replenishment. Experimental results show that the proposed methods turns out to outperform conventional methods including Flash, FLC, Motion-JPEG, MPEG-1, and MPEG-4.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.100-103
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• 2008

In this paper, we propose H.264 Encoder integrating Intra Prediction, Deblocking filter, Context-Based Adaptive Variable Length Coding, and Motion Estimation encoder module. This designed module can be operated in 440 cycle for one-macroblock. To verify the Encoder architecture, we developed the reference C from JM 9.4 and verified the our developed hardware using test vector generated by reference C. The designed circuit can be operated in 166MHz clock system, and has 1800k gate counts using Charterd 0.18um process including SRAM memory. Manufactured chip has the size of $6{\times}6mm$ and 208 pins package.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.358-362
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• 2005

디지털 비디오 압축기술은 멀티미디어 응용분야의 핵심으로 현재 빠르게 보급되어 최근에는 디지털비디오 압축 관련 국제 표준안 중 MPEG-4와 H.264가 발표되었다. 유연성이 좋은 MPEG-4와 달리H.264는 비디오 프레임의 효율적인 압축과 신뢰성을 강조 한다. 특히 H.264의 압축 기술은 카메라폰이나 DMB등의 작은 크기의 영상에서 고품질의 영상을 보다 효율적으로 제공 한다. 이에 본 논문은 현존하는 다른 비디오 코딩 표준과 비교할 때 코딩 효율이 기준의 두 배인 새로운 비디오 코딩 표준 H.264/AVC에서 사용하는, 변환 및 양자화를 연구하고 이를 기존의 정지영상 표준안인 JPEG나 JPEG 2000과 비교 분석하여 H.264/AVC의 공간적 압축인 인트라 코딩이 더 좋은 효과를 나타낸다는 것을 검증한 후 이를 토대로 하드웨어 설계언어인 VHDL언어를 이용하여 설계하고 FPGA칩인 XCV1000E에 다운로드 하여 칩 레벨의 시뮬레이션을 수행하여 설계된 변환 및 양자화 모듈을 검증하였다. 설계된 변환 및 양자화 모듈은 DMB 및 핸드폰 카메라와 같이 작은 정지 영상 압축에 응용이 가능하다.

• Journal of Multimedia Information System
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• v.5 no.3
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• pp.201-208
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• 2018

High Efficiency Video Coding range extensions (HEVC RExt) is a kind of extension model of HEVC. HEVC RExt was specially designed for dealing the high quality images. HEVC RExt is very essential for studio editing which handle the very high quality and various type of images. There are some problems to dealing these massive data in studio editing. One of the most important procedure is re-encoding and decoding procedure during the editing. Various codecs are widely used for studio data editing. But most of the codecs have common problems to dealing the massive data in studio editing. First, the re-encoding and decoding processes are frequently occurred during the studio data editing and it brings enormous time-consuming and video quality loss. This paper, we suggest new video coding structure for the efficient studio video editing. The coding structure which is called "ultra-low delay (ULD)". It has the very simple and low-delayed referencing structure. To simplify the referencing structure, we can minimize the number of the frames which need decoding and re-encoding process. It also prevents the quality degradation caused by the frequent re-encoding. Various fast coding algorithms are also proposed for efficient editing such as tool-level optimization, multi-serve based distributed coding and SIMD (Single instruction, multiple data) based parallel processing. It can reduce the enormous computational complexity during the editing procedure. The proposed method shows 9500 times faster coding speed with negligible loss of quality. The proposed method also shows better coding gain compare to "intra only" structure. We can confirm that the proposed method can solve the existing problems of the studio video editing efficiently.

• ETRI Journal
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• v.29 no.3
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• pp.390-392
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• 2007

In this paper, we propose a new error concealment (EC) method using inter-layer correlation for scalable video coding. In the proposed method, the auxiliary motion vector (MV) and the auxiliary mode number (MN) of intra prediction are interleaved into the bitstream to recover the corrupted frame. In order to reduce the bit rate, the proposed method encodes the difference between the original and the predicted values of the MV and MN instead of the original values. Experimental results show that the proposed EC outperforms the conventional EC by 2.8 dB to 6.7 dB.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.2
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• pp.93-101
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• 2017

This paper proposes an algorithm for adaptive loop filter (ALF) complexity reduction in the decoding process. In the original ALF algorithm, filtering for I frames is performed in the frame unit, and thus, all of the pixels in a frame are filtered if the current frame is an I frame. The proposed algorithm is designed on top of the local gradient calculation. On both the encoder side and the decoder side, homogeneous areas are checked and skipped in the filtering process, and the filter coefficient calculation is only performed in the inhomogeneous areas. The proposed algorithm is implemented in Joint Exploration Model (JEM) version 3.0 future video coding reference software. The proposed algorithm is applied for frame-level filtering and intra configuration. Compared with the JEM 3.0 anchor, the proposed algorithm has 0.31%, 0.76% and 0.73% bit rate loss for luma (Y) and chroma (U and V), respectively, with about an 8% decrease in decoding time.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.278-279
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• 2013

최근에 완료된 HEVC(High Efficiency Video Coding) 비디오 압축 표준은 H.264/AVC에 비해 2배 이상 향상된 압축 효율을 제공한다. 현재 진행 중인 HEVC 확장 (extension) 작업에서는 손실 및 무손실 부호화에서 4:2:2 및 4:4:4 색차 포맷과 최대 12비트 깊이를 지원하는 고급 프로파일을 개발하고 있다. 현재까지 개발된 HEVC의 CABAC(Context-based Adaptive Binary Arithmetic Coding)은 손실 부호화 환경에 적합하게 설계되었기 때문에 무손실 부호화 환경에서 최적의 부호화 성능을 제공하지 못한다. 본 논문에서는 4:4:4 색차 포맷 영상의 무손실 화면내 부호화 환경에서 잔여 신호의 통계적 특성을 고려한 향상된 CABAC 잔여 데이터 부호화 방법을 제안한다. 실험 결과를 통해, 본 논문에서 제안하는 향상된 CABAC 방법이 무손실 화면내 부호화에서 기존의 CABAC 방법에 비해 평균 약 2.41% 의 비트 수를 감소시키는 것을 확인했다.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.2
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• pp.143-151
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• 2016

This paper presents new prediction methods to improve compression performance of the so-called near-lossless RGB-domain image coder, which is designed to effectively decrease the memory bandwidth of a system-on-chip (SoC) for image processing. First, variable block size (VBS)-based intra prediction is employed to eliminate spatial redundancy for the green (G) component of an input image on a pixel-line basis. Second, inter-color prediction (ICP) using spectral correlation is performed to predict the R and B components from the previously reconstructed G-component image. Experimental results show that the proposed algorithm improves coding efficiency by up to 30% compared with an existing algorithm for natural images, and improves coding efficiency with low computational cost by about 50% for computer graphics (CG) images.

• Journal of Information Processing Systems
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• v.18 no.2
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• pp.235-244
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• 2022

Many new techniques have been adopted in HEVC (High efficiency video coding) standard, such as quadtree-structured coding unit (CU), prediction unit (PU) partition, 35 intra-mode, and so on. To reduce computational complexity, the paper proposes two optimization algorithms which include fast CU depth range decision and fast PU partition mode decision. Firstly, depth range of CU is predicted according to spatial-temporal correlation. Secondly, we utilize the depth difference between the current CU and CU corresponding to the same position of adjacent frame for PU mode range selection. The number of traversal candidate modes is reduced. The experiment result shows the proposed algorithm obtains a lot of time reducing, and the loss of coding efficiency is inappreciable.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.129-138
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• 2014

This paper proposes a fast intra prediction method to reduce encoding time for the HEVC(high-efficiency video coding) encoder. The proposed fast Intra prediction method uses quadtree structure and SATD(Sum of Absolute Transformed Differences). In HEVC, a $8{\times}8$ SATD value using $8{\times}8$ hadamard transform is used to calculate a SATD value for $8{\times}8$ or larger blocks. The proposed method calculates the best SATD value by using each $8{\times}8$ SATD result in $16{\times}16$ or larger blocks. After that, the proposed method removes a candidate mode for RDO(Rate-Distortion Optimization) based on comparing SATD of the candidate mode and the best SATD. By removing candidate modes, the proposed method reduces the operation of RDO and reduces total encoding time. In $8{\times}8$ block, the proposed method uses additional $4{\times}4$ SATD to calculat the best SATD. The experimental results show that the proposed method achieved 5.08% reduction in encoding time compared to the HEVC test model 12.1 encoder with almost no loss in compression performance.