• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.201-202
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• 2014

고효율 비디오 부호화/복호화 표준인 HEVC(High Efficiency Video Coding)는 ITU-T(VCEG)와 ISO-IEC(MPEG)이 JCT-VC라는 팀을 이루어 공동으로 표준화를 진행 하였다. 이 표준에서는 동영상 압축의 대표적 기술인 인트라 예측 방법을 사용하며, 기존 H.264/AVC 보다 더욱 다양한 방향의 예측을 통한 부호화 및 복호화의 효율을 가져온다. 제안하는 방법은 다양한 방향의 화소 예측에 사용되는 율-왜곡 최적화 방법의 계산량을 개선하는 방법으로, 주변 화소의 변화량을 이용하여 선택적인 모드를 사용하는 고속화 알고리즘을 통해 기존 방법보다 약 20%의 부호화 속도 향상을 가져오는 방법이다.

• 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.

• 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 SD
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• v.44 no.12
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• pp.93-101
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• 2007

Small area and low power implementation are important requirements for various multimedia processing hardware, especially for mobile environment. This paper presents a hardware architecture of H.264/AVC Intra Prediction module aiming on small area and low power. A single arithmetic unit was shared and processed sequentially for all mode decisions and computations to predict an image frame. As a result, we could get smaller area and smaller memory size compared to other existing implementations. The proposed architecture was verified using the Altera Excalibur device, and the implemented hardware has been described in Verilog-HDL and synthesized on Samsung STD130 0.18um CMOS Standard Cell Library using Synopsys Design Compiler. The synthesis result was about 11.9K logic gates and 1078 byte internal SRAM and the maximum operating frequency was 107Mhz. It consumes 879,617 clocks to process one QCIF frame, which means it can process 121.5 QCIF$(176\times144)$ frames per second, therefore it shows that it can be used for real time H.264/AVC encoding of various multimedia applications.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.582-590
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• 2010

he rate-distortion optimization (RDO) method in the H.264/AVC encoder is a technology that improves the coding efficiency, but increases the computational complexity. In this paper, a fast Intra mode decision algorithm using DCT (Discrete Cosine Transform) coefficients distribution is proposed to reduce the H.264 encoder complexity. The proposed method reduces the encoder complexity on average 68.40%, while the coding efficiency is slightly decreased compared with the H.264/AVC encoder.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.598-601
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• 2011

스케일러블 비디오 코딩은 레이어간 예측 기능을 이용하여 시뮬케스트 코딩에 비해 코딩 효율을 높인다. 하지만 스케일러블 비디오 코딩의 레이어간 예측으로는, 인트라 픽셀(inta pixel). 모션 정보(motion vector information), 레지듀얼(residual)등의 예측이 수행되는데, 이는 많은 계산 시간을 소요하게 되며, 시뮬케스트에 비해 코딩 시간이 증가하게 된다. 특히 인코더의 경우, 가장 최적의 모드를 선택하기 위하여, 기존 H.264 AVC에서 사용하는 예측을 수행한 뒤, 부가적으로 스케일러블 비디오 코딩의 레이어간 예측을 수행하기 때문에, 하나의 영상이 많은 레이어를 포함할수록 인코딩에 의한 계산부하가 매우 증가하게 된다. 본 논문에서는 이를 해결하기 위해, 멀티 코어 이용하여 레이어별로 병렬처리가 가능하도록 하는 스케일러블 비디오 인코더의 구조를 제안한다. 이로써 하나의 영상이 포함하는 레이어의 수가 증가함에 따라 발생하는 인코딩 계산 부하를 줄이도록 하였다. 그리하여 본 논문에서 제안하는 구조를 적용하였을 때, 2개의 공간영역으로의 스케일러빌리티를 가지는 영상들에 대해서는 평균 24.8%의 속도가 향상되었고, 1개의 공간영역과 1개의 화질 영역으로의 스케일러빌리티를 가지는 영상들에 대해서는 평균 82%의 속도 향상을 보였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.79-86
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• 2008

H.264/AVC is the newest international video coding standard developed by the joint ITU-T and ISO/IEC standards organizations. This newest video coding standard offers much higher coding efficiency than the H.261, H.263 and MPEG-4. But it has high computing complexity and high H/W resources wasting problem. This paper described the two unit parallel pipeline structure. This new structure comparing with standard model decreased the computing complexity of 67% and the H/W resources waste of 3%.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.1009-1018
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• 2015

In video coding, the first frame of a GOP is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the intial QP for the first frame encoding affects the first frame as well as the following frames. To determine the initial QP that maximizes the PSNR of a GOP, several algorithms which uses the ratio of the PSNR of the I frame and the PSNR of P frames of a GOP have been proposed. In this paper, we propose a new traffic model that can be used to determine the optimal initial QP simply and exactly in algorithms that use the PSNR ratio. We first analyze the characteristics of the PSNR ratio of I and P frames and the PSNR of a GOP, and then propose a new traffic model which can represent the characteristics and determine the optimal intial QP. It is shown by experimental results that the initial QP determination method with the proposed model can predict an optimal initial QP whose difference from the optimal value is less than 2. The proposed scheme can also generate the PSNR performance better than that of the existing JVT algorithm.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.341-348
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• 2016

HEVC is the next compression standard and is expected to be used widely replacing the conventional H.264/AVC standard. The compression ratio of the HEVC is twice times than H.264/AVC, whereas its computational complexity is increased by up to 40%. Many research efforts have been made to reduce the computational complexity and to speed up encoding. For intra coding, the rough mode decision (RMD) is commonly applied. The rate-distortion optimization (RDO) process to decide the best mode is too complex so that RMD chooses the candidate modes with a simple process and sends the candidates to RDO process. However, for large-size blocks, the RMD also requires considerable computations. In this paper, a down-sampling scheme is proposed for the RMD process. The reference pixel loading, predicted pixel generation are performed using the down-sampled pixel data. When the proposed scheme is applied to the RMD, the computational complexity is reduced by 70% with a marginal bitrate increase of 0.04%. In terms of area of hardware-based RMD, the gate count and the buffer size is reduced 33% and 66%, respectively.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.158-165
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• 2014

High Efficiency Video Coding (HEVC), the latest video coding standard, has twice of the compression efficiency compared to AVC/H.264 under the same image quality condition. To obtain the improved efficiency, however, it was adopted for many methods which need complicated calculation, and the time complexity of HEVC was increased more than that of AVC/H.264. To solve this problem, the various fast algorithms have been researched. In this paper, we propose a fast intra prediction mode decision method which uses result of Rough Mode Decision (RMD) and Most Probable Mode (MPM). The proposed method selects a best predicted mode by comparing each predicted directions which are calculated through RMD and MPM. We applied the proposed method to HM 10.0 and conducted an comparing experiment in All-Intra environment. The experiment result showed that total encoding time is reduced by about 26% on average with about a 0.8% loss of BD-rate.