• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.564-568
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• 2007

H.264/AVC는 최신의 국제 비디오 압축 표준으로 가변블록크기 지원, 다중 참조 프레임 움직임 보상 등의 기법으로 이전의 압축 표준인 MPEG-4, H.263등에 비해 비슷한 화질에서 비트율을 거의 50%정도 줄였다. 이러한 기법들로 압축 효율성이 높아진 반면, 계산 복잡도는 증가하게 되었다. 따라서 본 논문에서는 움직임 벡터 예측인 MVP를 이용하여 시간적 상관성을 고려하고 프레임 내의 주위 매크로블록 모드정보에 가중치를 부여하여 부호화를 매크로블록의 최종 모드를 빠르게 선택하는 기법을 제안한다. 실험에서 JM10.2의 모드 선택기법과 비교한 결과, 평균 85%이상 선택한 모드가 동일함을 보여주었다.

• Journal of Korea Multimedia Society
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• v.14 no.7
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• pp.858-865
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• 2011

In order to allow the user to efficiently browse, select, and retrieve a desired video part without having to deal directly with GBytes of compressed data, classification of shot motion characteristic has to be carried out as a preparation for such user interaction. The organization of video information for video database requires segmentation of a video into its constituent shots and their subsequent characterization in terms of content and camera movement in shot. In order to classify shot motion, it is a conventional way to use element of motion vector. However, there is a limit to estimate global camera motion because the way that uses motion vectors only represents local movement. For shot classification in terms of motion information, we propose a new scheme consisting of partial decoding of INTRA pictures and comparing the x, y displacement vector curve between the decoded I-frame and next P-frame in compressed video data.

• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.222-235
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• 2008

Recently, as growing of high definition media services like HDTV and IPTV, fast moving picture manipulation techniques need to meet what those services require. Especially, a fast reduced-size image extracting method is required in the areas of video indexing and video summary Conventional DC image extracting methods, however, can't be applied to H.264/AVC streams since a spatial domain prediction scheme is adopted in H.264/AVC intra mode. In this paper, we propose a theoretical method for extracting a thumbnail image from an H.264/AVC intra frame in the frequency domain. Furthermore, the proposed scheme can extract the thumbnail very fast since all operations are applied to transform coefficients directly, after a general equation for the thumbnail extraction in nine H.264/AVC intra prediction modes is introduced, an LUT(Look Up Table) for each mode is designed. Through the implementation and performance evaluation, while the subject quality difference between the output of our scheme and a conventional output is negligible, the former can extract the thumbnail faster then the latter by up to 63%.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.405-414
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• 2014

High Efficiency Video Coding(HEVC) obtains high compression ratio by applying recursive quad-tree structured coding unit(CU). However, this recursive quad-tree structure brings very high computational complexity to HEVC encoder. In this paper, we present fast CU decision algorithm in recursive quad-tree structure. The proposed algorithm estimates initial CU size before CTU encoding and checks the proposed condition using Coded Block Flag(CBF) and Rate-distortion cost to achieve the fast encoding time saving. And, intra mode estimation is also possible to be skipped using the CBF values acquired during the inter PU mode estimations. Experiment results shows that the proposed algorithm saved about 49.91% and 37.97% of encoding time according to the weighting condition.