• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.77-82
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• 2008

H.264 is a video coding standard of ITU-T and ISO/IEC, and widely spreads its application due to its high compression ratio more than twice that of MPEG-2 and high image quality. It has different architecture depending on demands since it is a lied from small image of QVGA to large size of HD. In this paper, We propose a scalable architecture for intra-prediction of H.264 decoders. The proposed scheme has a scalable architecture that can accommodate up to 4 processing elements depending on performance demands and can reduce the number of access to memory using efficient memory management so as to be energy-efficient. We design the intra-prediction unit using Verilog-HDL and verily it by prototyping using an FPGA. The performance is analyzed using the results of design.

• Journal of Broadcast Engineering
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• v.20 no.5
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• pp.687-696
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• 2015

JCT-VC (Joint Collaborative Team on Video Coding) continues developing HEVC/Screen Content Coding (HEVC/SCC) as an extension for efficiently coding screen content videos, including computer animations, graphics, and electrical documents, based on HEVC/Range extension (HEVC/RExt.). Color space conversion from RGB space being captured from CCD sensors is popular in natural video coding. However, the conversion is often undesired for screen contents because of a significant loss in perceptual quality. Therefore, several coding tools including cross-component prediction (CCP) and in-loop adaptive color space transform (ACST) have been developed for an efficient screen content video coding in order to reduce the redundancies between color spaces while maintaining the original color space. In this paper, we review the two coding tools, i.e., CCP and ACST exploiting the correlation in the RGB color space and conduct the performance analysis of the coding tools. In our simulation results, CCP and ACST provide 11.7% BD-rate saving and 16.4% BD-rate saving, respectively, while the two coding tools provide 18.2% BD-rate saving in total. Following this idea, if the two coding tools are exclusively selected, we provide 93% encoding measurement time with a 0.3% coding loss.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.103-112
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• 2011

Motion estimation (ME) is regarded as an important component in a video encoding process, because it consumes a large computation complexity. H.264/AVC requires additional computation overheads for fractional search and interpolation. This causes a problem that computational complexity is increased. In Motion estimation, SATD(Sum of Transform Difference) has the characteristics of a parabolic based on the minimum point. In this paper, we propose new prediction algorithm to reduce search point in motion estimation by sub-pixel interpolation characteristics. The proposed algorithm reduces the time of encoding process by decreasing computational complexity. Experimental results show that the proposed method reduces 20% of the computation complexity of motion estimation, while the degradation in video quality is negligible.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1172-1179
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• 2006

Recently, the H.264/AVC, which was standardized jointly by ISO/IEC and ITU-T, has been expanding its applications in various areas. This standard includes many advanced component techniques compared to the existing MPEG techniques. Intra prediction which is to predict the spatial data in an intra frame in one of them. But it has a serious defect that it needs large amount of calculation. To overcome this defect, this paper proposed a method to reduce about 60% of the amount of calculation with only O.02dB of image quality degradation. This method determines the calculation directly without much pre-calc cluation process by referring the left block(s) and upper blocks(s) that were processd already. Comparing to the exi sting methods, its image quality degradation is so small that it is expected to be used in many areas. Especially in the wireless appliances such as DMB phone which has restricted power source, we expect it would be used efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.536-541
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• 2007

In video coding standard H.264/AVC, motion estimation using multiple reference pictures improves compression efficiency but the efficiency depends upon image content not the number of reference pictures. So, the motion estimation includes a large amount of computation of no worth according to image. This paper proposes fast motion estimation algorithm that removes worthless computation in the motion estimation using multiple reference pictures. The proposed algorithm classifies a block into valid and invalid blocks for the multiple reference pictures and removes the workless computation by applying a single reference picture to the invalid block. To estimate the proposed algorithm's performance, image quality, bit rate, and motion estimation time are compared with ones of the conventional algorithm in the reference software JM 9.5. The simulation results show that the proposed algorithm can considerably save about 38.67% the averaged motion estimation time while keeping the image quality and the bit rate, whose are average values are -0.02dB and -0.77% respectively, as good as the conventional algorithm.

• Journal of Korea Multimedia Society
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• v.8 no.3
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• pp.345-354
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• 2005

Since motion estimation and motion compensation methods remove the redundant data to employ the temporal redundancy in images, it plays an important role in digital video compression. Because of its high computational complexity, however, it is difficult to apply to high-resolution applications in real time environments. If we have a priori knowledge about the motion of an image block before the motion estimation, the location of a better starting point for the search of an exact motion vector can be determined to expedite the searching process. In this paper presents the motion detection algorithm that can run robustly about recusive motion. The motion detection compares and analyzes two frames each other, motion of whether happened judge. Through experiments, we show significant improvements in the reduction of the computational time in terms of the number of search steps without much quality degradation in the predicted image.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.530-533
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• 2010

다시점 영상 부호화에서는 시점 간의 공간적 중복성을 이용하여 데이터 중복성을 제거하는 것이 중요하다. 독립적으로 부호화하는 동시 부호화 방법(simulcast)보다 부호화 효율이 더욱 향상하였지만 계산 복잡도가 증가하는 문제가 있다. 본 논문에서는 다시점 영상 부호화기의 계산 복잡도를 감소시키기 위한 빠른 모드 결정 방법을 제안한다. GOP 내의 양 끝에 위치하고 있는 기준 화면의 MAD를 계산하여 영역을 분할하고 영역 맵을 생성한다. 시점 간의 예측을 사용하는 시점의 경우 인접 시점의 기준 화면도 이용하여 영역을 분할한다. 생성된 맵은 비기준 화면의 부호화 시 적용되어 후보 모드를 조기에 판단한다. 이와 같은 방법을 적용한 후의 실험 결과, 화질의 손실이 거의 없으면서 부호화 시간은 평균 58.6% 감소하였고, 비트율은 평균 1.9% 증가하였다.

• Journal of Korea Multimedia Society
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• v.15 no.9
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• pp.1093-1101
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• 2012

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. Multi-view video coding exploits inter-view correlations among pictures of neighboring views and temporal correlations among pictures of the same view. Multi-view video coding which uses many cameras requires a method to reduce the computational complexity. In this paper, we proposed an efficient prediction structure to improve performance of multi-view video coding. The proposed prediction structure exploits an average distance between the current picture and its reference pictures. The proposed prediction structure divides every GOP into several small groups to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. Experimental results show that the proposed prediction structure shows good performance in image quality and bit-rates. When compared to the performance of hierarchical B pictures of Fraunhofer-HHI, the proposed prediction structure achieved 0.07~0.13 (dB) of PSNR gain and was down by 6.5(Kbps) in bitrate.

• Journal of Korea Technology Innovation Society
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• v.8 no.2
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• pp.783-808
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• 2005

초고속인터넷은 지상파방송, 케이블 TV, 위성방송에 이어 또 다른 미디어로 부각되기 시 작 하였다. 특히 통신과 방송이 융화되는 환경 하에서 IP-TV 서비스는 통신사업자나 방송사 업자에게 매우 중요한 중심 매체로 등장 되었고, 접속기술, 네트워크 기술, 동영상 압축기술등 기술의 발전은 더 이상 기술적인 요인이 IP-TV 서비스 활성화의 장애 요인으로 작용하지 않게 되었고, 서비스를 위한 장비 및 단말가격의 급격한 가격하락은 사업의 성공 가능성을 더 높여 주게 되었다. IP-TV 서비스는 보다 양질의 멀티미디어 서비스를 원하는 고객의 수요와 신규 고객을 유치하고 가입자를 Lock-in 시키며, 타 통신 사업자의 고객을 자사 고객으로 전환시키고자 하는 차별화 전략의 일환으로 통신사업자들이 적극적으로 도입하고 있다. 특히 망 진화에 따른 차세대 초고속인터넷 서비스 기술인 VDSL이나 Advanced 케이블모뎀을 이용 DVD 급 고화질의 IP-TV 서비스가 시작되면서 ARPU를 증대 시키고 다양한 수익원 개발의 일환으로 인터넷 접속서비스 외에 부가가치를 창출 할 수 있는 Killer Service로서 주목을 받고 있다. IP-TV 서비스는 가입자망의 진화 와 밀접하게 연관되어 전개되는 서비스로 Post-ADSL에 대한 예측과 IP-TV 서비스에 대한 설문조사 결과를 토대로 하여 예측 한 바에 의하면 Post-ADSL 가입자는 2005년 300만 명에서 2006년 480만으로 증가하고 2009년 1,024만 명에 이를 것으로 전망되고, IP-TV 서비스 가입자도 2005년 36만 명에서 2006년 88만으로 증가하고 2009년 382만 명으로 증가하는 것으로 예측되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.820-828
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• 2008

In order to achieve high coding efficiency, H.264/AVC video coding standard adopts the techniques such as variable block size coding, motion estimation with quarter-pel precision, multiple reference frames, rate-distortion optimization, and etc. However, these coding methods have a defect to greatly increase the complexity for motion estimation. Particularly, from multiple reference frame motion estimation, the computational burden increases in proportion to the number of the searched reference frames. Therefore, we propose the method to reduce the complexity by controlling the number of the searched reference frames in motion estimation. Proposed algorithm uses the optimal reference frame information in both $P16{\times}16$ mode and the adjacent blocks, thus omits unnecessary searching process in the rest of inter modes. Experimental results show the proposed method can save an average of 57.31% of the coding time with negligible quality and bit-rate difference. This method also can be adopted with any of the existing motion estimation algorithm. Therefore, additional performance improvement can be obtained.