• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.416-426
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• 2011

In this paper, we proposed an intra coding method with merging intra prediction mode to achieve intra coding gain. The proposed method uses signaling of prediction mode with merging prediction modes, which is different from the conventional method. If the number of blocks that has the same prediction mode compared to that to be predicted from neighboring blocks exceeds the predefined threshold, then the proposed method is used in order to reduce bits of intra prediction mode for coding efficiency. Otherwise the conventional method is used. Experimental results show the proposed method achieves the PSNR gain of about 0.05 dB in RD curve and reduces the bit rates about 1 % compared with H.264/AVC. In particular, the PSNR gain of about 0.1 dB in RD curve and reduces the bit rates about 1.7 % compared with H.264/AVC at low bit-rates. we can know that the proposed method is efficient tool at low bit-rates.

• Journal of Broadcast Engineering
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• v.23 no.4
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• pp.495-502
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• 2018

JVET (Joint Video Exploration Team) which explored evolving technologies of video coding with capabilities beyond HEVC (High Efficiency Video Coding), released a references software codec named the Joint Exploration Model (JEM) for performance verification of coding technologies. JEM has 67 intra prediction modes that extend the 35 modes of HEVC for intra prediction. Therefore, the enhancement of the coding performance is limited due to the overhead of prediction mode coding. In this paper, we analyze the probabilities of prediction modes selections, and then we propose a more efficient intra prediction mode coding based on the results of analyzed mode occurrence. In addition, we propose a context modeling for CABAC (Context-Adaptive Binary Arithmetic Coding) of the proposed mode coding. Experimental results show that the BD-rate gain is 0.02% on the AI (All Intra) coding structure compared to JEM 7.0. We need to optimize context modeling for additional coding performance enhancement.

• 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.

• ETRI Journal
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• v.30 no.4
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• pp.506-515
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• 2008

The H.264/AVC standard has adopted new coding tools such as intra-prediction, variable block size, motion estimation with quarter-pixel-accuracy, loop filter, and so on. The adoption of these tools enables an H.264/AVC-coded bitstream to have more information than was possible with previous standards. In this paper, we propose an effective spatial error concealment method with low complexity in H.264/AVC intra-frame. From information included in an H.264/AVC-coded bitstream, we use prediction modes of intra-blocks to recover a damaged block. This is because the prediction direction in each prediction mode is highly correlated to the edge direction. We first estimate the edge direction of a damaged block using the prediction modes of the intra-blocks adjacent to a damaged block and classify the area inside the damaged block into edge and flat areas. Our method then recovers pixel values in the edge area using edge-directed interpolation, and recovers pixel values in the flat area using weighted interpolation. Simulation results show that the proposed method yields better video quality than conventional approaches.

• 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.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.949-950
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• 2008

The intra prediction technique is the one of the key factors to the success of H.264. There are nine optional prediction modes for each $4{\times}4$ luma block and 4 modes for each $16{\times}16$ luma block. To reduce the intra mode bits efficiently, the most probable mode (MPM) is estimated by using the intra modes of the adjacent blocks, since intra modes for neighboring $4{\times}4$ luma blocks are correlated. In this paper, a new method for estimating the MPM is proposed by using the statistical distribution of intra modes of adjacent intra blocks. Experimental results show that the proposed method can achieve a coding gain of about 0.1dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.492-503
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• 2013

H.264/AVC has shown high coding efficiency by using various coding tools, including intra and inter prediction. However, there are still many more redundancy components in intra prediction than in inter prediction. In this paper, a novel intra prediction method is proposed with adaptive mode selection. The combined intra prediction modes and simplified gradient modes are added in order to refine the directional feature and gradation region. Suitable modes are selected according to the neighboring blocks that provide a high compression rate and lower computational complexity. The improvement of the proposed method is 1.96% in terms of the bitrate, 0.25 dB in PSNR, and 1.72 times in terms of the computational complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1144-1152
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• 2005

Intra prediction coding is one of the many coding-efficiency oriented tools of H.264/AVC, but it requires high computational complexity. Many fast intra coding algorithms have been proposed to reduce the computational complexity of intra prediction. While most of them have been focused on the mode decision methods themselves, we propose a fast algorithm in which new intra modes are substituted for the conventional intra modes so that the number of intra modes can be reduced. The simulation results show that the proposed method could reduce the encoding time of the overall sequence by $49\%$ without any noticeable degradation of the coding efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3C
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• pp.271-278
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• 2006

Rate-constrained coding is one of the many coding-efficiency oriented tools of H.264/AVC, but mode decision process of RDO(Rate distortion optimization) requires high computational complexity. Many fast mode decision algorithms have been proposed to reduce the computational complexity of mode decision. In this paper, we propose two algorithms for reduction of mode decision in H.264/AVC, which are the fast reference frame selection and selective intra prediction mode decision. Fast reference frame selection is efficient for inter predication and selective intra prediction mode decision can effectively reduce excessive calculation load of intra prediction mode decision. The simulation results showed that the proposed methods could reduce the encoding time of the overall sequences by 44.63% on average without any noticeable degradation of the coding efficiency.

• 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).