• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.510-519
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• 2011

Intra mode decision is a useful coding tool in Distributed Video Coding (DVC) for improving DVC coding efficiency for video sequences having fast motion. A major limitation associated with the existing intra mode decision methods, however, is that its efficiency highly depends on user-specified thresholds or modeling parameters. This paper proposes an entropy-based method to address this problem. The probabilities of intra and Wyner?Ziv (WZ) modes are determined firstly by examining correlation of pixels in spatial and temporal directions. Based on these probabilities, entropy of the intra and the WZ modes are computed. A comparison based on the entropy values decides a coding mode between intra coding and WZ coding without relying on any user-specified thresholds or modeling parameters. Experimental results show its superior rate-distortion performance of improvements of PSNR up to 2 dB against a conventional Wyner?Ziv coding without intra mode decision. Furthermore, since the proposed method does not require any thresholds or modeling parameters from users, it is very attractive for real life applications.

• 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 Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.765-770
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• 2012

In this paper, we proposed an effective hardware structure using DCT-based inra-prediction mode selection to reduce computational complexity caused by intra mode decision. In this hardware structure, the input block is transformed at first and then analyzed to determine its texture directional tendency. the complexity has solved by performing intra prediction in only predicted edge direction. $4{\times}4$ DCT is calculated in one cycle using Multitransform_PE and Inta_pred_PE calculates one prediction mode in two cycles. Experimental results show that the proposed Intra prediction encoding needs only 517 cycles for one macroblock encoding. This architecture improves the performance by about 17% than previous designs. For hardware implementation, the proposed intra prediction encoder is implemented using Verilog HDL and synthesized with Megnachip $0.18{\mu}m$ standard cell library. The synthesis results show that the proposed architecture can run at 125MHz.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.993-994
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• 2008

There are nine modes of the intra prediction for $4{\times}4$ luma blocks in H.264/AVC, each of which is identified by the prediction direction and reference pixels. Especially, mode 8 is modified to enhance coding efficiency, considering that the mode does not use left-bottom pixels although they are available. That is, we propose a modified intra prediction method of mode 8 which uses left-bottom pixels if available.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.492-499
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• 2019

HEVC is the high efficiency video coding standard, which provides better coding efficiency contrasted with the other video coding standard. But at the same time the computational complexity increases drastically. Thirty-five kinds of intra-prediction modes are defined in HEVC, while 9 kinds of intra prediction modes are defined in H.264/AVC. This paper proposes a fast rough mode decision (RMD) algorithm which adopts the smoothness of the up-reference pixels and the left-reference pixels to decrease the computational complexity. The three step search method is implemented in RMD process. The experimental results compared with HM13.0 indicate that the proposed algorithm can save 39.7% of the encoding time, while Bjontegaard delta bitrate (BDBR) is increased slightly by 1.35% and Bjontegaard delta peak signal-to-noise ratio (BDPSNR) loss is negligible.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.154-163
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• 2014

In this paper, there is suggested a fast intra prediction mode decision method in HEVC. To reduce the number of candidates in rough mode decision (RMD) process and rate-distortion optimization (RDO) process, the edge information and relative RMD cost are utilized. The experiment results show that the proposed method reduces encoding run-time by 26.81% with a negligible coding loss of 0.79% BD-rate on average.

• ETRI Journal
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• v.27 no.5
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• pp.511-524
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• 2005

In this paper, we propose a novel hardware architecture for an intra-prediction, integer transform, quantization, inverse integer transform, inverse quantization, and mode decision module for the macroblock engine of a new video coding standard, H.264. To reduce the cycle of intra prediction, transform/quantization, and inverse quantization/inverse transform of H.264, a reduction method for cycle overhead in the case of I16MB mode is proposed. This method can process one macroblock for 927 cycles for all cases of macroblock type by processing $4{\times}4$ Hadamard transform and quantization during $16{\times}16$ prediction. This module was designed using Verilog Hardware Description Language (HDL) and operates with a 54 MHz clock using the Hynix $0.35 {\mu}m$ TLM (triple layer metal) library.

• Journal of Broadcast Engineering
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• v.6 no.2
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• pp.187-194
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• 2001

The Advanced Intra Coding(AIC) mode included in the H.263+ which is for video ceding at low bit rates, selects one prediction direction of DCT coefficients among three directions for every intra macroblock. Based ()n the selected direction, It uses a different DCT scanning order, quantization scheme, and VLC table. The use of the AIC mode brings higher compression ratio and improved PSNR than the H.263 baseline. This paper proposes a simplified submode selection method for a direction of the DCT coefficient prediction for advanced ultra coding in H.263. Compared to the conventional method the proposed simplified method can achieve a similar coding Performance at computational complexity reduced to 1/7 and with much less memory requirement. The proposed method will be useful in implementing a simplified H.263 system.

• Journal of Broadcast Engineering
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• v.17 no.3
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• pp.471-479
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• 2012

Intra prediction is one of the significant techniques in H.264/AVC reference software; however, it has heavy computational complexity. In order to solve this problem, many fast algorithms have been proposed. In this paper, we propose a fast intra mode decision algorithm which predicts the edge direction of the current block using sub-sampled pixels to reduce high computational complexity of the H.264/AVC encoder. The proposed algorithm shows that it not only improves the coding performance but also reduces the computational complexity of the H.264/AVC encoder compared to previous algorithms. The experimental results show that the proposed algorithm achieves the encoding time reduction of 75.93% on an average with slight peak signal-to-noise ratio (PSNR) drop and bit-rate increment.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.190-206
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• 2011

We propose an adaptive combination scheme of intra and inter prediction modes, where uni-directional intra prediction, bi-directional intra prediction, and inter prediction method are adaptively selected in an EMB (extended macro block). For each EMB, after all inter blocks have been encoded and decoded, the reconstructed blocks are used as reference data for bi-directional intra prediction of other blocks. Whereas conventional intra coding scheme does not use the right and below side pixels of the current block as reference data, the proposed method uses those for bi-directional intra prediction mode. In this paper, we propose three advanced techniques; (a) filter design for bi-directional prediction, (b) adaptive coding order scheme which increases the chance to use the bi-directional intra prediction mode, (c) modification of syntax to represent coding order. The information for the coding order is informed to the decoder by using the modified syntax structure without adding any additional flag. The simulation results show that the proposed scheme reduces the BD-Rate by 0.5%, on average, compared to KTA.