• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.6 s.360
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• pp.42-49
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• 2007

CABAC(Context-based Adaptive Binary Arithmetic Coding) among various entropy coding schemes which are used to improve compression efficiency in H.264/AVC has a high hardware complexity and the fast calculation is difficult because data dependancy exists in the bit-serial process. In this paper, the proposed architecture efficiently compose the renormalization process of binary arithmetic encoder which is an important part of CABAC used in H.264/AVC. At every clock cycle, the input symbol is encoded regardless of the iteration of the renormalization process for every input symbol. Also, the proposed architecture can deal with the bitsOutstanding up to 127 which is adopted to handle the carry generation problem and encode input symbol without stall. The proposed architecture with three-stage pipeline has been synthesized using the 0.18um Dongbu-Anam standard cell library and can be operated at 290MHz.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.137-151
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• 2008

H.264/AVC is showed high coding efficiency more than previous video coding standard by using new coding tools. Specially, Variable block-based motion estimation and Rate-Distortion Optimization are very important coding tools in H.264/AVC. These coding tools have high coding efficiency, however the encoder complexity greatly increase due to these coding tools. In this paper, we propose early SKIP mode decision and selective inter/intra mode decision to reduce the computational complexity. Simulation results show that the proposed method could reduce encoding time of the overall sequences by 30% on average than JM 10.2 without noticeable degradation of coding efficiency. Besides, the proposed method runs over twice as fast as the previous proposed Fast Coding Mode Selection method (FCMS)[5].

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.2
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• pp.48-56
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• 2009

We propose a fast intra mode skip decision algorithm for H.264/AVC video encoding. Although newly added MB encoding algorithms based on various prediction methods increase compression ratio, they require a significant increase in the computational complexity because we calculate rate-distortion(RD) cost for all possible MB coding modes and then choose the best one. In this paper, we propose a fast mode decision algorithm based on an adaptive motion vector map(AMVM) method for H.264/AVC video encoding to reduce the processing time for the inter frame. We verify that the proposed algorithm generates generally good performances in PSNR, bit rates, and processing time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6C
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• pp.450-458
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• 2008

In this paper, we propose a real-time stereoscopic display system based on H.264/AVC. We initially acquire stereo-view images from stereo web-cam using OpenCV library. The captured images are converted to YUV 4:2:0 format as a preprocess. The input files are encoded by stereo-encoder, which has a proposed estimation structure, with more than 30 fps. The encoded bitstream are decoded by stereo-decoder reconstructing left and right images. The reconstructed stereo images are postprocessed by stereoscopic image synthesis technique to offer users more realistic images with 3D effect. Experimental results show that the proposed system has better encoding efficiency compared with using a conventional stereo CODEC(coder and decoder) and operates with real-time processing and low complexity suitable for an application with a mobile environment.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.112-120
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• 2013

In this paper, we propose high-performance H.264/AVC CAVLC encoder for UD video real time processing. Statistical values are obtained in one cycle through the parallel arithmetic and logical operations, using non-zero bit stream which represents zero coefficient or non-zero coefficient. To encode codeword per one cycle, we remove recursive operation in level encoding through parallel comparison for coefficient and escape value. In oder to implement high-speed circuit, proposed CAVLC encoder is designed in two-stage {statical scan, codeword encoding} pipeline. Reducing the encoding table, the arithmetic unit is used to encode non-coefficient and to calculate the codeword. The proposed architecture was simulated in 0.13um standard cell library. The gate count is 33.4Kgates. The architecture can support Ultra Definition Video ($3840{\times}2160$) at 100 frames per second by running at 100MHz.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.180-183
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• 2011

본 논문에서는 HEVC(High Efficiency Video Coding) 부호화기에서 사용되는 TU(Transform Unit) 분할이 깊이에 따라 속도와 화질과 압축률에 미치는 영향을 분석한다. 현재 HD 영상의 표준 부호화기로 사용되던 H.264/AVC 를 대신할 차세대 부호화기인 HEVC 에 대한 표준화 작업이 이루어지고 있으며 이러한 HEVC 부호화기의 특징 중 하나로 영상 압축 시 CU, PU, TU 로 세분화 된 단위를 사용한다는 점을 들 수 있다. HEVC의 reference software 인 HM 의 경우 기존 H.264/AVC 에 비하여 UHD 영상에서 최대 40%에 가까운 비트 절감률을 보이지만 최적화가 이루어지지 않아 실시간 부호화에는 적합하지 않은 속도를 보인다. HM 에서는 각 CU 나 TU 에 대하여 quadtree 형식으로 분할하여 부호화를 수행한 후 최적의 분할 형태를 취하는 방식을 사용하기 때문에 많은 시간을 소요하게 되며 분할되는 깊이에 비례하여 기하급수적으로 속도가 느려지게 된다. 본 논문에서는 TU 가 분할되는 깊이가 부호화 화질과 속도에 어느 정도 영향을 미치는지를 분석하고 화질 손상을 최소화 하는 최적의 TU 분할 깊이를 제안하여 보기로 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1486-1488
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• 2009

본 논문은 비디오 압축 기술인 H.264/AVC와 H.264/SVC에 적용할 수 있는 인증 목적의 효율적인 프레자일(fragile) 워터마킹 기법을 제안한다. 제안된 워터마킹 기법은 H.264/AVC 비디오 부호화기에서 압축률을 높이기 위해 사용하는 매크로블록(MB) 예측 모드들을 특징 값으로 추출하여 콘텐츠 제공자의 비밀키로 암호화 후 워터마크로 사용하는 인증 기법으로, 이는 공간적, 시간적 그리고 SNR 확장성을 가지는 H.264/SVC에도 확장하여 적용할 수 있다. 워터마크 삽입은 최적의 예측 모드를 찾기 위한 모드 결정과정에서 수행되어 워터마크 후에도 최적화 된 콘텐츠를 얻을 수 있으며, 간단한 연산을 엔코더와 결합시켜 낮은 시간 증가율을 가진다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.63-71
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• 2009

In this paper, a new low-complexity distortion estimation method for H.264 rate-distortion optimized mode decision is proposed. The coding processes, such as DCT, quantization, inverse quantization, inverse DCT, and reconstruction are needed to compute the distortion in an H.264 encoder. To reduce these processes, we estimate distortion using integer operations with coefficients obtained in the quantization process. Inverse quantization, inverse DCT, and reconstruction processes are not needed by the proposed method. For quantization parameters 24 to 36, experimental results show that the time saving of rate-distortion optimized mode decision is on average 29 % and as high as 42 % with negligible degradation in coding performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.285-286
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• 2010

최근 HDTV, 블루레이 등 고해상도, 고품질 디지털 멀티미디어 응용 기술의 보급으로 인하여, 고해상도, 고품질 비디오 부호화 기술에 대한 중요성이 증가하고 있다. 현재 고해상도 비디오 부호화에 사용되는 H.264/AVC 표준의 인트라 부호화 기술은 인터 부호화 기술의 복잡도가 크게 증가하는 고해상도 영상에서 인터 부호화 기술에 비해 낮은 복잡도를 가진 부호화기 및 복호화기의 구현이 가능하다는 장점을 가지고 있다. 그러나 인트라 부호화 기술은 인터 부호화 기술에 비하여 압축 효율이 매우 낮다는 문제점이 있다. 본 논문에서는 고해상도 영상을 위한 새로운 $16{\times}16$ 블록의 인트라 예측 기술을 제안한다. 실험을 통하여 제안한 새로운 $16{\times}16$ 인트라 예측 기술을 사용할 경우, HD급 고해상도 영상에 대해 평균 2.8%의 부호화 효율을 증가시킬 수 있음을 보여준다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.771-777
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• 2012

This paper proposes a binary arithmetic encoder of CABAC using a Common Operation Unit including the three modes. The binary arithmetic encoder performing arithmetic encoding and renormalizer can be simply implemented into a hardware architecture since the COU is used regardless of the modes. The proposed binary arithmetic encoder of CABAC includes Context RAM, Context Updater, Common Operation Unit and Bit-Gen. The architecture consists of 4-stage pipeline operating one symbol for each clock cycle. The area of proposed binary arithmetic encoder of CABAC is reduced up to 47%, the performance of proposed binary arithmetic encoder of CABAC is 19% higher than the previous architecture.