• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.3 s.303
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• pp.53-62
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• 2005

In the decoding process of interframe Wavelet coding, the Wavelet transform requires huge computational complexity. Since the decoder may need to be used in various devices such as PDAs, notebooks, or PC, the decoder's complexity should be adapted to the processor's computational power. So, it is natural that the low complexity codec is also required for scalable video coding. In this paper, we develop a method of controlling and lowering the complexity of the spatial Wavelet transform while sustaining the same coding efficiency as the conventional spatial Wavelet transform. In addition, the proposed method may alleviate the ringing effect for slowly changing image sequences.

• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.1018-1025
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• 2011

Scalable Video Coding (SVC) extension of H.264/AVC is a new video coding standard for media convergence by providing diverse videos of different spatial-temporal-quality layers with a single bitstream. Recently, real-time SVC codecs are being developed for the application areas of surveillance video and mobile video, etc. This paper presents the design and implementation of a H.264/SVC decoder based on an embedded DSP using Open SVC Decoder (OSD) which is a real-time software decoder designed for the PC environment. The implementation consists of porting C code of the OSD software from PC to DSP environment, profiling the complexity performance of OSD with further optimization, and integrating the optimized decoder into the TI Davinci EVM (Evaluation Module). 50 QCIF/CIF frames or 15 SD frames per second can be decoded with the implemented DSP-based SVC decoder.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1513-1526
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• 2009

The SVC (Scalable Video Coding) scheme can be effectively used for reducing the redundancy and for improving the coding efficiency but, it requires very high computational complexities. In order to accelerate the successful standardization and commercialization of the Advanced Terrestrial-DMB service, it is necessary to overcome this problem. For this aim, in this paper, we propose an efficient aggregated encoder control algorithm, which shows better performances than the conventional control scheme. Computer simulation result shows that the proposed scheme performs about up to 0.3dB better than those of the conventional scheme. Additionally, based on this control scheme, we propose a fast mode decision method by constraining the redundant coding modes based on the statistical properties of the quantization parameter in the spatial scalable encoder. Through computer simulations, it is shown that the proposed control schemes reduce the heavy computational burden up to 12% compared to the conventional scheme, while keeping the objective visual qualify very high.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.4
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• pp.309-318
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• 2004

This paper proposes the H.264-based selective fine granular scalable (FGS) coding scheme that selectively uses the temporal prediction data in the enhancement layer. The base layer of the proposed scheme is basically coded by the H.264 (MPEG-4 Part 10 AVC) visual coding scheme that is the state-of-art in codig efficiency. The enhancement layer is basically coded by the same bitplane-based algorithm of the MPEG-4 (Part 2) fine granular scalable coding scheme. In this paper, we introduce a new algorithm that uses the temproal prediction mechanism inside the enhancement layer and the effective selection mechanism to decide whether the temporally-predicted data would be sent to the decoder or not. Whenever applying the temporal prediction inside the enhancement layer, the temporal redundancies may be effectively reduced, however the drift problem would be severly occurred especially at the low bitrate transmission, due to the mismatch bewteen the encoder's and decoder's reference frame images. Proposed algorithm selectively uses the temporal-prediction data inside the enhancement layer only in case those data could siginificantly reduce the temporal redundancies, to minimize the drift error and thus to improve the overall coding efficiency. Simulation results, based on several test image sequences, show that the proposed scheme has 1∼3 dB higher coding efficiency than the H.264-based FGS coding scheme, even 3∼5 dB higher coding efficiency than the MPEG-4 FGS international standard.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.596-610
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• 2007

In order to reduce the complexity of SVC encoding, we introduce a fast mode decision method in the enhancement layers of spatial scalability by selectively performing the inter-layer residual prediction of SVC. The Inter-layer residual prediction coding in Scalable Video Coding has a large advantage of enhancing the coding efficiency since it utilizes the correlation between two residuals from a lower spatial layer and its next higher spatial layer. However, this entails the dramatical increase in the complexity of SVC encoders. The proposed method is to analyze the characteristics of integer transform coefficients for the subtracted signal for two residuals from lower and upper spatial layers. Then it selectively performs the inter-layer residual prediction coding and rate-distortion optimizations in the upper spatial enhancement layer if the SAD values of residuals exceed adaptive threshold values. Therefore, by classifying the residuals according to the properties of integer-transform coefficients only with SAD of residuals between two layers, the SVC encoder can perform the inter-layer residual coding selectively, thus significantly reducing the total required encoding time. The proposed method results in reduction of the total encoding time with 51.5% in average while maintaining the RD performance with negligible amounts of quality degradation.

• Journal of Broadcast Engineering
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• v.17 no.5
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• pp.765-780
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• 2012

In this paper, we propose a fast mode decision method that determines the coding unit depth for enhancement layers to improve an encoding speed of a scalable video encoder based on HEVC. To decide the coding unit depth of the enhancement layer, firstly, the coding unit depth of the corresponded coding unit in the basement layer is employed. At this stage, the final CU depth is decided by calculating the rate-distortion costs of one lower depth to one upper depth of the referenced depth. The proposed method can reduce a computational load since it does not calculate the rate-distortion costs for all the depths of a target CU. We found that the proposed algorithm decreases encoding complexity of 26% with approximately 1.4% bit increment, compared with the simulcast encoder of the HM 4.0.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.35-41
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• 2009

The H.264/SVC enables network-adaptive video transmission to smart device which uses wireless network. But, quality scalability of H.264/SVC does not consider personal subjective image quality. In addition, its network efficiency also does not optimized because it uses MGS(Medium Grained Scalability) and CGS(Coarse Grained Scalability). Thus, this paper proposed a new scalable ROI algorithm for not only subjective image quality improvement but also network adaptation. To experiment our proposed a scheme, we added designed algorithm to JSVM(Joint Scalable Video Model) open source video codec of H.264/SVC. Experiment was performed according to the pre-defined scenario for simulating various network conditions. Finally, experimental result showed our proposed scalable ROI scheme. It is better than traditional non-selective scheme in subjective video quality.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.211-213
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• 2014

최근 4K 이상의 초고해상도 동영상 콘텐츠가 제작되고 있고 그에 따라 많은 기업이 UHD TV 제품을 제작 판매 하고 있다. 따라서 이에 대응할 수 있는 새로운 코덱이 필요하고 그를 위해 HEVC가 개발되었다. 그러나 아직 HEVC의 부호화 효율을 위한 scalable 부호화 방식이 개발 중이다. 초고해상도 비디오 콘텐츠를 다양한 단말기에서 사용할 수 있도록 하기 위해서는 scalable 부호화 방식이 연구개발 되어야 한다. 본 논문에서는 HEVC 이전 버전 코덱인 H.264/AVC를 기반으로 한 scalable 부호화 방식 중 공간적 scalability에 대해 설명하고 여러 방법으로 간단하게 적용시켜 scalable 부호화 방식의 효율의 성능을 예측 평가해 본다. 이 방식은 dowm-sampling한 영상을 HEVC로 부호화하고 이를 up-sampling한 영상과 원영상의 차영상을 HEVC로 부호화하여 전송하는 방식이다. 여기서는 이 방식의 결과를 토대로 이 방식의 문제점을 지적하고 이를 토대로 한 향후의 연구방향을 제시한다.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.749-754
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• 2002

In this paper, We propose a titrate allocation method in which the bitrates of the videos for the lower layer are restricted by constant titrate, but those of the higher layer are assigned to have the uniform picture quality, for the multiplexing system of multiple spatial scalable video sources. We first find an approximated model of distortion-bitrate for the MPEG-2 spatial scalable video coding system, then we obtain the bitrate for each source to have constant distortion ratio among the sources by using the approximated model parameters for real-time simple implementation. It is shown by simulation that the proposed bandwidth allocation can keep almost constant picture Quality ratio among the sources of higher layer.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.845-850
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• 2010

In this paper, a method for transmitting layered SVC streams in differentiated MBSFN channels is presented. Scalable coded video streams are transmitted in modulation channels of different efficiency that it achieves reduced resource consumption compared to non-scalable AVC stream. When utilizing with Raptor FEC, the combined effect is enhanced service coverage with providing minimum video quality at the edge of the service area, than the case of AVC.