• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.1-11
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• 2007

H.264/AVC uses variable block sizes to achieve significant coding gain. It has 7 different coding modes having different motion compensation block sizes in Inter slice, and 2 different intra prediction modes in Intra slice. This fine-tuned new coding feature has achieved far more significant coding gain compared with previous video coding standards. However, extremely high computational complexity is required when rate-distortion optimization (RDO) algorithm is used. This computational complexity is a major problem in implementing real-time H.264/AVC encoder on computationally constrained devices. Therefore, there is a clear need for complexity reduction algorithm of H.264/AVC such as fast mode decision. In this paper, we propose a fast mode decision with early $P8\times8$ mode rejection based on block size activity using large block history map (LBHM). Simulation results show that without any meaningful degradation, the proposed method reduces whole encoding time on average by 53%. Also the hybrid usage of the proposed method and the early SKIP mode decision in H.264/AVC reference model reduces whole encoding time by 63% on average.

• Journal of Korea Multimedia Society
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• v.10 no.8
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• pp.997-1003
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• 2007

H.264/AVC enhances inter-frame coding performance adopting new intra and inter mode prediction in inter-frame motion prediction. H.264 encoder provides performance superior to existing standards with the prediction modes. Instead of enhanced performance, however, both predictions increase complexity of encoder and demand a lot of coding time. This paper proposes a method using local statistics of resultant intra mode, my and mode map to predict inter mode. There are relationship between intra and inter mode, and we can predict inter mode using neighboring macroblocks' resultant mode and motion vector according to the contents of frame. The experimental results show that the proposed algorithm reduces encoding time by 31% on average with a negligible loss of PSNR and bitrate.

• 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.

• 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.15 no.3
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• pp.380-390
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• 2010

The most recent standard video codec, H.264/AVC achieves significant coding efficiency by using a rate-distortion optimization(RDO). The RDO is a measurement for selecting the best mode which minimizes the Lagrangian cost among several modes. As a result, the computational complexity is increased drastically in encoder. In this paper, a method for fast intra prediction mode decision is proposed to reduce the RDO complexity. To speed up Intra$4{\times}4$ and Chroma Intra encoding, the proposed method decides the case that MPM (Most Probable Mode) is the best prediction mode. In this case, the RDO process is skipped, and only MPM is used for encoding the block in Intra$4{\times}4$. And the proposed method is also applied to the chroma Intra prediction mode in a similar way to the Intra$4{\times}4$. The experimental results show that the proposed method achieves an average encoding time saving of about 63% with negligible loss of PSNR (Peak Signal-to-Noise Ratio).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.7
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• pp.3018-3038
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• 2020

In the stereoscopic or multiview display, the depth video illustrates visual distances between objects and camera. To promote the computational efficiency of depth video encoder, we exploit the intra prediction of depth videos under Versatile Video Coding (VVC) and observe a diverse distribution of intra prediction modes with different coding unit sizes. We propose a hybrid scheme to further boost fast depth video coding. In the first stage, we adaptively predict the HADamard (HAD) costs of intra prediction modes and initialize a candidate list according to the HAD costs. Then, the candidate list is further improved by considering the probability distribution of candidate modes with different CU sizes. Finally, early termination of CU splitting is performed at each CU depth level based on the Bayesian theorem. Our proposed method is incorporated into VVC intra prediction for fast coding of depth videos. Experiments with 7 standard sequences and 4 Quantization parameters (Qps) validate the efficiency of our method.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.4
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• pp.235-241
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• 2016

Compared to the former H.264 standard, the number of the prediction modes has highly increased in HEVC intra prediction. Compression efficiency and accurate prediction are significantly improved. However, the computational complexity increases as well. To solve this problem, this paper proposes the new scheme where not only prediction modes but also block partition candidate are early chosen. Compared to the original intra prediction in HEVC, the proposed scheme achieves about 38% reduction in processing cycles with a marginal loss in compression efficiency.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.77-88
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• 2000

This paper presents an approach for rate control by adaptively selecting macroblock modes in video coding.The problem of rate control has been investigated by many authors where quantizer level is adjustedbased on the buffer fullness. The proposed approach is different fron the previous ones [4] id that it finds the optimal decision curve rather than finding a set of the modes. Proposed algorithm extends the coding decision options for rate control to motion/no-motion compensation as well as inter/intra decisions. Instead of having a fixed motion/no-notion compensation or inter/intra decision curve, one can utilize an adaptive decision curvebased on the characteristics of input frames so that the PSNR at a given bit rate is maximized. Therefore, the proposed approach provides better rate control than simple quantizer feedback approach interns of visual quality. The curve is obtained by utilizing simulated annealing optimization technique. Thealgorithm is implemented and simulations are compared with other approaches within H.261 video codec.

• Journal of Broadcast Engineering
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• v.21 no.2
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• pp.140-148
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• 2016

HEVC(High Efficient Video Coding) has twice times better compression ratio than H.264/AVC, but since the computational complexity has significantly increased in the encoder side, it may cause difficulty in real-time SW implementation in the encoder side. This paper proposes two methods about fast intra prediction. First, fast mode and prediction unit decision method using transform coefficients of the original block is proposed. and second, fast prediction unit decision method using coded block flag(cbf) is proposed. The proposed method achieves 42% encoder speed up with 0.8% bitrate increase compared with HM16.0.