• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.83-85
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• 2008

현행 지상파 DMB(Digital Multimedia Broadcasting)에서는 최대 CIF급 해상도의 동영상을 384 Kbps 정도의 비트율로 압축하여 비디오 CD급의 화질을 제공한다. 따라서 큰 화면을 통해 DMB 방송을 시청할 경우 해상도 부족 등으로 인한 화질 열화를 느낄 수 있다. 이와 같은 문제를 해결하기 위한 방안으로 계층적으로 부호화된 비트스트림을 서로 다른 채널로 전송하는 고품질 AT-DMB 시스템이 연구되고 있다. 더불어, 계층변조 기술을 이용하여 추가적인 전송대역폭을 확보하고, 계층적 비디오 부호화 기술을 이용하여 고품질 이동 멀티미디어 방송을 제공하는 고품질 T-DMB 방식이 개발되고 있다. 이와 같은 AT-DMB 방식으로 사용자에게 안정된 고품질 비디오 서비스를 제공하기 위해서는 계층적 비디오 부호화를 고려한 효율적인 AV다중화 및 동기화 구조에 대한 연구가 필수적으로 요구 된다. 본 논문에서는, 이와 같은 고품질 AT-DMB 시스템을 위해서 각 계층 ES(Elementary stream)을 MPEG-4 over MPEG-2 시스템과 Eureka-147 DAB 시스템을 통해 서로 다른 채널로 전송한다. 계층별 전송으로 인한 시간 지연에 대처하여 수신입력부에서는 각각의 계층으로 전송된 ES들이 동기화 되어 복호화 되도록 SVC의 계층적 비트스트림 구조와 적응적으로 동작되는 다중화 시스템구조를 제작하였다.

• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.152-164
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• 1996

This paper describes the hardware architecture and implementation trade-offs of the Grand Alliance HDTV video encoder system. The implemented video encoder accepts video in 1125 line(30Hz) interlaced format, and produces a bit-stream compliant with the motion picture experts group version 2(MPEG-2) standards. The encoder processing includes large- area motion estimation and an advanced rate control mechanism. To keep the system complexity realizable, we adopt a fast hierarchical motion estimation method and developed its hardware architecture. Furthermore an adaptive perceptual quantization method is adopted to improve the perceptual quality. The developed system Is based on the 4-way parallel processing architecture and is implemented by using programmable IC, memory IC, and special-purpose processors such as DCT and motion estimation processors.

• Journal of Korea Multimedia Society
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• v.12 no.4
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• pp.492-501
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• 2009

Information on movement of objects in videos can be used as an important part in categorizing and separating the contents of a scene. This paper is proposing a shape-based movement-matching algorithm to effectively find the movement of an object in video streams. Information on object movement is extracted from the object boundaries from the input video frames becoming expressed in continuous 2D shape information while individual 2D shape information is converted into a lD shape feature using the shape descriptor. Object movement in video can be found as simply as searching for a word in a text without a separate movement segmentation process using the sequence of the shape descriptor listed according to order. The performance comparison results with the MPEG-7 shape variation descriptor showed that the proposed method can effectively express the movement information of the object and can be applied to movement search and analysis applications.

• Journal of the Korea Computer Industry Society
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• v.6 no.5
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• pp.801-812
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• 2005

H.264/AVC is the international video coding standard which has significant improvements of coding efficiency. ITU-T(International Telecommunication Union-Telecommunication standardization sector) and MPEG(Moving Picture Experts Group) adopts various complex coding tool such as variable block size motion, multiple reference frames, quarter-pel motion estimation/compensation (ME/MC) and rate-distortion(RD) optimization, etc. H.264 reference model employs complex mode decision technique based on RD optimization which requires high computational complexity. In this paper, we propose an efficient coding mode decision based on the cost distribution of RD in the macroblock coding mode sequence. Simulation results show that the proposed method reduces encoding time by 34% on average and save the number of computing RD cost by 82%.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.4
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• pp.381-387
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• 2002

In this paper, an efficient method to find shot boundaries in the MPEG video stream data is proposed. For this purpose, we first assume that the histogram difference value(HDV) and pixel difference value(PDV) as an one dimensional signal and apply the median filter to these signals. The output of the median filter is subtracted from the original signal to produce the median filtered difference(MFD). The MFD is a criterion of shot boundary. In addition a neural network is employed and trained to find exactly cut boundary. The proposed algorithm shows that the cut boundaries are well extracted, especially in a dynamic video.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.185-188
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• 2005

DTV-to-DMB 비디오 변환을 위해서는 기본적으로 MPEG-2 MP@HL의 HDTV/SDTV급 영상을 MPEG-4 AVC BP@1.3의 QCIF/QVGA/WDF/CIF급 영상으로 변환하는 과정이 필요하다. 본 논문에서는 DTV-to-DMB 비디오 변환을 위해 DTV의 고해상도 영상을 DMB의 저해상도 영상으로 축소하는 방식을 제안하고 있다. DTV-to-DMB 비디오 변환은 실시간 변환이 고려되어야 하며, 실시간 변환을 위해서는 축소 방식의 시간 복잡도가 고려 되어야 한다. 일반적으로 낮은 시간 복잡도를 갖는 영상 축소 방식으로는 대상 영상의 하나의 픽셀을 참조 영상 내 대응하는 픽셀들 중 한 픽셀을 선택하여 결정하는 방식(Just Get A Pixel)이 있으며, 참조 영상의 대응하는 픽셀들의 평균값을 선택하는 방식 (Average Shrink)과 중간값을 선택하는 방식 (Median Shrink)이 있다. 한편, DTV 영상은 인터레이스 방식을사용하며 DMB의 프로그레시브 방식 영상으로 변환 처리 과정에서, 움직임이 큰 영상에 대해 사물의 윤곽선이 계단 모양으로 보이는 재그 에지 (Jagged Edge) 현상이 나타난다. 본 논문에서는 대상 영상의 한 픽셀을 참조 영상의 대응하는 픽셀들 중 중간 위치의 몇 개 픽셀들과 주변 인접 픽셀들을 선출하여 그것들의 평균값 (Average)을 구하여 결정하는 Center Average 축소 방식을 제안한다. 제안된 방식은 기본적인 축소 방식을 기반으로 하여 낮은 시간 복잡도를 갖으며, 재그 에지 (Jagged Edge) 현상을 줄여 준다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.298-302
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• 2004

An electronic commerce model is proposed which distributes digital content in mobile environment. This model resolves the problems caused by various digital content and complex distribution structure. The online distribution systems under the wireless environment include many different factors from the conventional offline and wired networks. Furthermore, the multimedia content may be propagated more easily and illegally. The scheme to protect the rights and profits of people related to the copyrights of digital content is needed. In this paper a framework for electronic commerce of content distribution under the wireless environment based on MPEG-21 is proposed. This model can be applied to the digital rights management system and utilized to protect the rights of trading entities in online distribution of electronic commerce.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.297-304
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• 2004

TV-Anytime specification provides metadata standards for personalized broadcasting service. For personalized broadcasting service, the metadata is transmitted through the specific way to the employed broadcasting system. In an MPEG-2 environment. the metadata can be transmitted using Sections, objects within a DSM-CC Object Carousel or modules within a DSM-CC Data Carousel. In this paper, we introduce a TV-Anytime metadata delivery method within Object Carousel which is used in ATSC-ACAP and DVB-MHP, We describe an actual example of unidirectional personalized broadcasting which is implemented on an ATSC-ACAP data broadcasting receiver, where the metadata is delivered as objects within a DSM-CC Object Carousel.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.354-362
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• 2012

Recently, High Efficiency Video Coding (HEVC) is under development jointly by MPEG and ITU-T for the next international video coding standard. Compared to the previous standards, HEVC supports variety of splitting units, such as coding unit (CU), prediction unit (PU), and transform unit (TU). Among them, it has been known that the recursive quadtree structure of CU can improve the coding efficiency while the encoding complexity is increased significantly. In this paper, a simple conditional probability to predict the early termination condition of recursive unit structure is introduced. The proposed conditional probability is estimated based on Bayes' formula from local statistics of rate-distortion costs in encoder. Experimental results show that the proposed method can reduce the total encoding time by about 32% according to the test configuration while the coding efficiency loss is 0.4%-0.5%. In addition, the encoding time can be reduced by 50% with 0.9% coding efficiency loss when the proposed method was used jointly with HM4.0 early CU termination algorithm.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.493-498
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• 2009

Bluetooth is a popular wireless data transmission method with low power consumption, but it has low data transmission rate. Thus, although many video stream players of a local or network file exist, there have been few players of video stream transmitted via Bluetooth. MPEG-4 AVC/H.264 codec is one of video codecs available with best compression rates for a certain quality, so a H.264 encoder seems to be adequate for video stream to be transmitted via Bluetooth. In this paper, we present a DirectShow filter based player of video stream encoded by H.264 codec, which is transmitted via Bluetooth. Details on the design and implementation of this program are described. Experimental results are shown to demonstrate the validity of the implemented program using various video samples.