• 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.28 no.4
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• pp.425-434
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• 2006

We propose a fast macroblock mode prediction and decision algorithm based on contextual information for Pslices in the H.264/AVC video standard, in which the mode prediction part is composed of intra and inter modes. There are nine $4{\times}4$ and four $16{\times}16$ modes in the intra mode prediction, and seven block types exist for the best coding gain based on rate-distortion optimization. This scheme gives rise to exhaustive computations (search) in the coding procedure. To overcome this problem, a fast inter mode prediction scheme is applied that uses contextual mode information for P-slices. We verify the performance of the proposed scheme through a comparative analysis of experimental results. The suggested mode search procedure increased more than 57% in speed compared to a full mode search and more than 20% compared to the other methods.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.434-440
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• 2013

With polymer properties and ceramic volume fraction as design variables, the optimal structure of 1-3 piezocomposites has been determined to maximize the thickness mode electromechanical coupling factor. When the piezocomposite vibrates in a thickness mode, inter-pillar resonant modes are likely to occur between lattice-structured piezoceramic pillars and polymer matrix, which significantly deteriorates the performance of the piezocomposite. In this work, a new method to design the structure of the 1-3 type piezocomposite is proposed to maximize the thickness mode electromechanical coupling factor while preventing the occurrence of the inter-pillar modes. Genetic algorithm was used for the optimal design, and the finite element analysis method was used for the analysis of the inter-pillar mode.

• ETRI Journal
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• v.29 no.6
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• pp.736-744
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• 2007

We propose a fast macroblock (MB) mode prediction and decision algorithm based on temporal correlation for P-slices in the H.264/AVC video standard. There are eight block types for temporal decorrelation, including SKIP mode based on rate-distortion (RD) optimization. This scheme gives rise to exhaustive computations (search) in the coding procedure. To overcome this problem, a thresholding method for fast inter mode decision using a MB tracking scheme to find the most correlated block and RD cost of the correlated block is suggested for early stop of the inter mode determination. We propose a two-step inter mode candidate selection method using statistical analysis. In the first step, a mode is selected based on the mode information of the co-located MB from the previous frame. Then, an adaptive thresholding scheme is applied using the RD cost of the most correlated MB. Secondly, additional candidate modes are considered to determine the best mode of the initial candidate modes that does not satisfy the designed thresholding rule. Comparative analysis shows that a speed-up factor of up to 70.59% is obtained when compared with the full mode search method with a negligible bit increment and a minimal loss of image quality.

• Journal of Broadcast Engineering
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• v.9 no.3
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• pp.214-224
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• 2004

In this paper, an adaptive spatio-temporal predictive coding based on the H.264 is proposed for 3D immersive media encoding, such as 3D image processing, 3DTV, and 3D videoconferencing. First, we propose a spatio-temporal predictive coding using the same view and inter-view images for the two TPPP, IBBP GOP (group of picture) structures 4hat are different from the conventional simulcast method. Second, an 2D inter-view direct mode for the efficient prediction is proposed when the proposed spatio-temporal prediction uses the IBBP structure. The 2D inter-view direct mode is applied when the temporal direct mode in B(hi-Predictive) picture of the H.264 refers to an inter-view image, since the current temporal direct mode in the H.264 standard could no: be applied to the inter-view image. The proposed method is compared to the conventional simulcast method in terms of PSNR (peak signal to noise ratio) for the various 3D test video sequences. The proposed method shows better PSNR results than the conventional simulcast mode.

• ETRI Journal
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• v.28 no.6
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• pp.721-731
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• 2006

A fast intra skip detection algorithm based on the ratedistortion (RD) cost for an inter frame (P-slices) is proposed for H.264/AVC video encoding. In the H.264/AVC coding standard, a robust rate-distortion optimization technique is used to select the best coding mode and reference frame for each macroblock (MB). There are three types of intra predictions according to profiles. These are $16{\times}16$ and $4{\times}4$ intra predictions for luminance and an $8{\times}8$ intra prediction for chroma. For the high profile, an $8{\times}8$ intra prediction has been added for luminance. The $4{\times}4$ prediction mode has 9 prediction directions with 4 directions for $16{\times}16$ and $8{\times}8$ luma, and $8{\times}8$ chrominance. In addition to the inter mode search procedure, an intra mode search causes a significant increase in the complexity and computational load for an inter frame. To reduce the computational load of the intra mode search at the inter frame, the RD costs of the neighborhood MBs for the current MB are used and we propose an adaptive thresholding scheme for the intra skip extraction. We verified the performance of the proposed scheme through comparative analysis of experimental results using joint model reference software. The overall encoding time was reduced up to 32% for the IPPP sequence type and 35% for the IBBPBBP sequence type.

• ETRI Journal
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• v.32 no.4
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• pp.577-587
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• 2010

The layered coding structure of scalable video coding (SVC) with adaptive inter-layer prediction causes noticeable computational complexity increments when compared to existing video coding standards. To lighten the computational complexity of SVC, we present a fast algorithm to speed up the inter-mode decision process. The proposed algorithm terminates inter-mode decision early in the enhancement layers by estimating the rate-distortion (RD) cost from the macroblocks of the base layer and the enhancement layer in temporal, spatial, and inter-layer directions. Moreover, a search range decision algorithm is also proposed in this paper to further increase the motion estimation speed by using the motion vector information from temporal, spatial, or inter-layer domains. Simulation results show that the proposed algorithm can determine the best mode and provide more efficient total coding time saving with very slight RD performance degradation for spatial and quality scalabilities.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.13-16
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• 2000

This paper introduces a more effective usage of the limited OVSF cod in compressed mode which is used during inter-frequency/inter-system handover in UTRA(Universal mobile telecommunications system) Terrestrial Radio Access). The usager is to use dynamic common channel which is shared by several users during the compressed mode.

• Journal of Korea Multimedia Society
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• v.11 no.2
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• pp.163-174
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• 2008

The H.264/AVC provides gains in compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards. However, to achieve such high coding efficiency, the complexity of H.264/AVC encoder is also increased drastically than previous ones, mainly because of mode decision. In this paper, we propose a three-step mode decision algorithm for fast encoding in H.264/AVC. In the first step, we select skip mode or inter mode by considering the temporal correlation and spatial correlation. In the second step, if the result of the first step is INTER mode, we select one group between two groups for final mode. In the third step, we select final mode by exploiting the pixel values of error macroblock or the modes of adjacent macroblocks. Simulations show that the proposed method reduces the encoding time by 42% on average without any significant PSNR losses.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.223-228
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• 2004

현재 모바일 환경에서 PDA, 휴대폰 등으로 많은 캐릭터 영상들이 서비스되고 있다. 본 논문에서는 이러한 캐릭터 영상들의 무손실 동영상 압축 방법을 제안한다. 캐릭터 영상은 256컬러 인덱스 영상이며. 영상간에 유사한 컬러로 제작된다. 제안한 압축방법은 기존 MPEG, H.264에서 사용하는 동영상 부호화 기법이외에도 캐릭터 영상의 특성을 반영한다. 각 블록 타입을 DC mode, INTER mode, 및 INTRA mode로 분류하는데 다른 mode와 유사하게 DC mode는 캐릭터 영상의 특성을 활용한다. INTER mode는 예측 에러의 분포를 분석하여 세 가지 예측 방법들 중에서 압축 효율이 우수한 방법으로 처리한다. 또한 INTRA mode는 4개의 서브모드로 나누어 압축 효율성을 제고한다. 12개의 캐릭터 실험 영상들은 각각 12장의 영상으로 구성되는데, 제안 압축 방법을 적용하면 평균 1.44:1의 압축율을 얻는다. 또한 실험결과에서는 각 블록 타입의 비율 및 INTRA와 INTER블록의 비율을 조절하여 얻어 지 는 압축율의 변화를 조사하였다.