• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.129-138
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• 2014

This paper proposes a fast intra prediction method to reduce encoding time for the HEVC(high-efficiency video coding) encoder. The proposed fast Intra prediction method uses quadtree structure and SATD(Sum of Absolute Transformed Differences). In HEVC, a $8{\times}8$ SATD value using $8{\times}8$ hadamard transform is used to calculate a SATD value for $8{\times}8$ or larger blocks. The proposed method calculates the best SATD value by using each $8{\times}8$ SATD result in $16{\times}16$ or larger blocks. After that, the proposed method removes a candidate mode for RDO(Rate-Distortion Optimization) based on comparing SATD of the candidate mode and the best SATD. By removing candidate modes, the proposed method reduces the operation of RDO and reduces total encoding time. In $8{\times}8$ block, the proposed method uses additional $4{\times}4$ SATD to calculat the best SATD. The experimental results show that the proposed method achieved 5.08% reduction in encoding time compared to the HEVC test model 12.1 encoder with almost no loss in compression performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.145-146
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• 2015

HEVC(High Efficient Video Coding)는 H.264/AVC 대비 하여 50% 정도의 높은 압축률을 보이지만 인코더의 복잡도가 크게 증가하였다. 이러한 높은 복잡도로 인한 실사용에 있어서의 문제를 줄이기 위하여 본 논문에서는 변환계수의 분포와 cbf(coded block flag)를 이용하여 예측블록의 크기를 빠르게 결정짓는 방법을 제안한다. 제안된 방법은 HM16.0 대비 42%의 부호화 속도를 향상시켰으며 1.9%의 성능 감소를 갖는다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.361-362
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• 2021

본 논문에서는 VVC(Versatile Video Coding) 부호화 시간 감소를 위해 ISP(Intra Sub-Partition) 모드의 복잡도를 감소시키는 방법을 제안한다. 이 방법은 ISP 모드 적용을 위한 RDO(Rate-Distortion Optimization) 탐색을 수행할 때 현재 블록의 모양에 따라 특정 ISP 모드 방향을 사전에 제한하여 RDO 과정을 생략함으로써 부호화 시간을 단축한다. 실험 결과, 기존 VVC 방법 대비 BDBR(Bjøntegaard Delta Bit Rate) 측면에서 AI(All Intra) 구성하에 Y 채널에서 0.01%, Cb, Cr 채널에서 각각 -0.04%, -0.08% 변화로 2%의 부호화 시간 감소의 결과를 얻을 수 있었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1060-1067
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• 2000

MPEG-4 visual coding is an object-based system. The current video coding standards, H.261, MPEG-1, and MPEG-2 encode frame by frame. On the other hand, MPEG-4 separately encodes several objects, such as video objects and audio objects, in the same frame. Each transmitted object is decoded and composed in one frame. Shape coding is a process of coding visual objects in a frame. In this paper we present conformance test method for MPEG-4 shape decoders. This paper reviews the basic shape decoding standard, and proposes conformance test methods for BAB type decoder, and CAE decoder for intra and inter VOPs. Our test generates all possible cases of shape motion vector difference and context.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.490-496
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• 2006

H.264 is the most recent video coding standard, containing improved error resilience tools than previous video compression schemes. This paper shows an analysis of the dependency of error concealment (EC) performance on the expected number of correctly received neighboring macroblock(MB)s for a lost MB, applying error concealment schemes to the raster scan mode that is used in the previous video coding standard and the flexible macroblock ordering (FMO) which is one of error-resilience tools in H.264. We also present simulation results and performance evaluation with various packet loss rates. Simulation results show that the FMO mode provides better EC performances of $1{\sim}9dB$ PSNR improvements compared to the raster scan mode because of larger expected number of correctly received neighboring MBs. The PSNR improvement by FMO mode becomes higher as the intra-frame period is larger and the packet loss rate is higher.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.391-399
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• 2006

We propose a novel low complexity video encoder, at the expense of a complex decoder, where video frames are intra-coded periodically and frames in between successive intra-coded frames are coded efficiently using a proposed irregular binning technique. We investigate a method of forming an irregular binning which is capable of quantizing any value effectively with only small number of bins, by exploiting the correlation between successive frames. This correlation is additionally exploited at the decoder, where the quality of reconstructed frames is enhanced gradually by applying POCS(projection on the convex sets). After an image frame is reconstructed with the irregular binning information at the proposed decoder, we can further improve the resulting quality by modifying the reconstructed image with motion-compensated image components from the neighboring frames which are considered to contain image details. In the proposed decoder, several iterations of these modification and re-projection steps can be invoked. Experimental results show that the performance of the proposed coding scheme is comparable to that of H.264/AVC coding in m mode. Since the proposed video coding does not require motion estimation at the encoder, it can be considered as an alternative for some versions of H.264/AVC in applications requiring a simple encoder.

• ETRI Journal
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• v.25 no.6
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• pp.489-502
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• 2003

This paper presents an MPEG-4 video codec, called MoVa, for video coding applications that adopts 3G-324M. We designed MoVa to be optimal by embedding a cost-effective ARM7TDMI core and partitioning it into hardwired blocks and firmware blocks to provide a reasonable tradeoff between computational requirements, power consumption, and programmability. Typical hardwired blocks are motion estimation and motion compensation, discrete cosine transform and quantization, and variable length coding and decoding, while intra refresh, rate control, error resilience, error concealment, etc. are implemented by software. MoVa has a pipeline structure and its operation is performed in four stages at encoding and in three stages at decoding. It meets the requirements of MPEG-4 SP@L2 and can perform either 30 frames/s (fps) of QCIF or SQCIF, or 7.5 fps (in codec mode) to 15 fps (in encode/decode mode) of CIF at a maximum clock rate of 27 MHz for 128 kbps or 144 kbps. MoVa can be applied to many video systems requiring a high bit rate and various video formats, such as videophone, videoconferencing, surveillance, news, and entertainment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.1055-1061
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• 2008

H.264 is the prominent video coding standard in various applications such as real-time streaming and digital multimedia broadcasting, since it provides enhanced compression performance, error resilience tools, and network adaptation. Compression efficiency of H.264 has been improved, however, it requires more computing and memory access than traditional methods. In this paper we proposed adaptive intra fast algorithm for real-time video surveillance system reducing the encoding complexity of H264/A VC. For this aim, temporal interrelationship between macroblock in the previous and the current frame is used to decide the encoding mode of macroblock fast. As a result, though video quality was deteriorated a little, less than 0.04dB, and bit rate was somewhat increased in suggested method, however, proposed method improved encoding time significantly and, in particular, encoding time of an image with little changes of neighboring background such as surveillance video was more shortened than traditional methods.

• Journal of Broadcast Engineering
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• v.7 no.4
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• pp.300-309
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• 2002

The object of this paper is to make temporal direct mode clear by providing a solution to the following problem : if the co-located block in the list 1 reference picture for direct mode has only the 1ist 1 motion vector or both the 1ist 0 and list 1 motion vectors, then which motion vector will be used for the direct mode motion vector calculation\ulcorner This paper also shows how to derive reference picture index and direct mode motion vector for each list in order to guarantee the high coding efficiency. when the co-located macroblock is in intra mode. Furthermore, the reasonable calculation methods for the direct mode motion vectors in the various cases are presented. Finally, experimental results show that the proposed temporal direct mode provides the comparable performance against the spatial direct mode. Therefore, the simulation proves that the proposed temporal direct mode is acceptable.

• Journal of Broadcast Engineering
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• v.10 no.1 s.26
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• pp.77-82
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• 2005

We propose a highly Integrated motion estimation processor (MEP) for efficient video compression in an SoC platform. When compressing video by the standards like MPEG-4 and H.263, the macroblock related functions motion compensation. mode decision, motion vector prediction, and motion vector difference calculation require the frequent intervention of MCU. Thus the proposed MEP incorporates those functions with the motion estimation capability to reduce the number of interrupts to MCU, which can lead to a highly efficient SoC system. For low-power consumption, the proposed MEP can prevent the temporally static area from motion estimation or can skip the half-pel motion estimation for those macroblocks whose modes are decided as INTRA.