• 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.

• ETRI Journal
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• v.31 no.5
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• pp.610-612
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• 2009

We present intra-mixture prediction (IMP) mode for intra prediction and an enhanced estimation method for most probable mode (MPM). IMP mode supports more flexibility in intra prediction by mixing $4{\times}4$ blocks and $8{\times}8$ blocks in one macroblock, while the enhanced MPM estimation extends the number of referenced neighboring blocks and efficiently uses their prediction modes depending on their positions. Simulation results show that the combination of both proposed methods provides a bit reduction in the Bj${\phi}$ntegaard delta bitrate by an average of 2.56% compared to H.264/AVC.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.141-142
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• 2015

본 논문에서는 HEVC(High Efficiency Video Coding)을 위한 고속 부호화 알고리즘을 제안한다. 제안 방법은 HEVC 의 화면내 부호화 과정에서 주변 부호화 모드 정보인 MPM(Most Probable Mode)과 RMD(Rough Mode Decision) 과정의 결과로 얻어지는 후보 모드들의 상관관계를 이용하여 높은 계산 복잡도를 가지는 RDO(Rate-Distortion Optimization) 과정이 고려하는 후보의 개수를 줄여 전체 부호화기의 부호화 복잡도를 낮춘다. 실험 결과에서는 제안 방법이 약 0.29% BD-rate 의 부호화 손실만으로 20.43%의 부호화 복잡도를 감소시켰음을 보인다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.71-74
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• 2013

차세대 동영상 표준 코덱인 High Efficiency Video Coding(HEVC)은 기존의 AVC/H.264 보다 동일 화질 대비 최대 약 2배의 압축 성능을 보여준다. 이러한 HEVC의 성능을 얻기 위하여 복잡한 연산이 많은 기법이 도입되었고 이로 인하여 HEVC의 시간 복잡도는 AVC/H.264보다 더욱 증가하였다. HEVC의 시간 복잡도를 줄이기 위해서 다양한 고속 알고리즘이 논의되고 있고 인트라 예측 모드에서의 고속 알고리즘 연구 또한 많은 연구가 이루어지고 있다. 본 논문에서는 인트라 예측 모드 결정과정에서 HEVC에 구현된 Rough mode decision(RMD)와 Most probable mode(MPM)의 결과를 활용하여 고속화된 최종예측 모드 결정 방법을 제안한다. 실험 결과, HM 10.0의 All Intra 환경을 기준으로 BD-rate에서 약 0.9%의 손실과 함께 평균 24%의 속도 향상을 얻을 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.3
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• pp.44-53
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• 2010

The H.264/AVC has been designed to use 9 directional intra prediction modes for removing spatial redundancy. It also employs high correlation between neighbouring block modes in sending mode information. For indication of the mode, smaller bits are assigned for higher probable modes and are compressed by predicting the mode with minimum value between two prediction modes of neighboring two blocks. In this paper, we calculated the statistical probability of prediction modes of the current block to exploit the correlation among the modes of neighboring two blocks with several test video sequences. Then, we made the probable prediction table that lists 5 most probable candidate modes for all possible combinatorial modes of upper and left blocks. By using this probability table, one of 5 higher probable candidate modes is selected based on RD-optimization to reduce computational complexity and determines the most probable mode for each cases for improving compression performance. The compression performance of the proposed algorithm is around 1.1%~1.50%, compared with JM14.2 and we achieved 18.46%~36.03% improvement in decoding speed.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.127-137
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• 2009

A practical algorithm of generating most probable states in decreasing order of probability of the network system state is suggested for approximating the performance of multi-mode network system using algebraic structure of the system states. Most complex system having network structure with multi-mode unit state is difficult to evaluate the performance or reliability due to exponentially increasing size of state space. Hence not an exact computing method but an approximated one is reasonable approach to solve the problem. To achieve the goal we should enumerate the network system states in order as a pre-processing step. In this paper, we suggest an improved algorithm of generating most probable multi-mode states to get the ordered system states efficiently. The method is compared with the previous algorithms in respective to memory requirement and empirical computing time. From the experiment proposed method has some advantages with regard to the criterion of algorithm performance. We investigate the advantages and disadvantage by illustrating experiment examples.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3A
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• pp.157-162
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• 2012

In this paper, we propose a new intra mode coding method using the candidate mode table. In the conventional HEVC, if the predicted most probable mode (MPM) is not same with the current prediction mode, the current prediction mode is encoded using the fixed length code (FLC). However, since a large number of modes are used in HEVC, the codeword length of FLC gets longer. In this paper, we generate the candidate mode table from neighboring blocks and encode the obtained intra mode index using Golomb-Rice code instead of FLC, when the predicted MPM is not identical to the current mode. From the experiment, we verified that the proposed method reduces the BD-rate by 0.5% on average, compared to the HEVC intra mode coding method.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.448-461
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• 2011

H.264/AVC significantly outperforms the previous video coding standards with many new coding tools. Among these tools, several intra-block coding tools can particularly improve coding efficiency. For intra prediction, H.264/AVC supports most probable mode in the entropy coding process to reduce syntax elements indicating intra prediction modes and most probable mode selection ratio is very high. Also, in general, natural images and videos have many homogeneous regions whose high correlation with neighbouring blocks. In this paper, we propose intra prediction mode SKIP mode using decoder-side prediction to improve the coding efficiency. The proposed method is determined the optimal prediction mode using only neighbouring block's information and coded on the basis of the conventional prediction/transform coding. And the prediction modes are not send to decoder at all. Skipped intra prediction mode is determined by decoder. Experimental results show that the proposed method achieves coding gains of 1.40% for common intermediate format(CIF), 3.24% for 720p sequences against the H.264/AVC JM 17.0 reference software.

• Structural Engineering and Mechanics
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• v.76 no.6
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• pp.675-685
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• 2020

As the classical response surface method (RSM), the polynomial RSM is so easy-to-apply that it is widely used in reliability analysis. However, the trade-off of accuracy and efficiency is still a challenge and the "curse of dimension" usually confines RSM to low dimension systems. In this paper, based on the univariate decomposition, the polynomial RSM is executed in a new mode, called as DPRSM. The general form of DPRSM is given and its implementation is designed referring to the classical RSM firstly. Then, in order to balance the accuracy and efficiency of DPRSM, its adaptive order revision around the most probable point (MPP) is proposed by introducing the univariate polynomial order analysis, noted as RDPRSM, which can analyze the exact nonlinearity of the limit state surface in the region around MPP. For testing the proposed techniques, several numerical examples are studied in detail, and the results indicate that DPRSM with low order can obtain similar results to the classical RSM, DPRSM with high order can obtain more precision with a large efficiency loss; RDPRSM can perform a good balance between accuracy and efficiency and preserve the good robustness property meanwhile, especially for those problems with high nonlinearity and complex problems; the proposed methods can also give a good performance in the high-dimensional cases.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.109-112
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• 2020

VVC uses 67 modes in intra prediction. Most probable mode (MPM) is used to reduce data for the representation of intra prediction mode. If the mode to send exists in the MPM candidate, the index of the MPM list is transmitted. If it does not exist in the MPM candidate, TBC encoding is applied. When TBC is applied in intra prediction, three are selected in order of low number mode and coded into 5 bits. The remaining modes except the mode encoded by 5 bits are encoded by 6 bits. In this paper, we examine the limitations of the TBC used in VVC intra prediction and propose an adaptive method that can encode more efficiently than conventional methods when using TBC in intra prediction. As a result, the coding efficiency of the overall coding performance is 0.01% and 0.04% in AI and RA, respectively, compared with the conventional coding method.