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Documents authored by Lu, Xin


Document
Fast Implementation of the Scalable Video Coding Extension of the H.264/AVC Standard

Authors: Xin Lu and Graham R. Martin

Published in: OASIcs, Volume 35, 2013 Imperial College Computing Student Workshop


Abstract
In order to improve coding efficiency in the scalable extension of H.264/AVC, an inter-layer prediction mechanism is incorporated. This exploits as much lower layer information as possible to inform the process of coding the enhancement layer(s). However it also greatly increases the computational complexity. In this paper, a fast mode decision algorithm for efficient implementation of the SVC encoder is described. The proposed algorithm not only considers inter-layer correlation but also fully exploits both spatial and temporal correlation as well as an assessment of macroblock texture. All of these factors are organised within a hierarchical structure in the mode decision process. At each level of the structure, different strategies are implemented to eliminate inappropriate candidate modes. Simulation results show that the proposed algorithm reduces encoding time by up to 85% compared with the JSVM 9.18 implementation. This is achieved without any noticeable degradation in rate distortion.

Cite as

Xin Lu and Graham R. Martin. Fast Implementation of the Scalable Video Coding Extension of the H.264/AVC Standard. In 2013 Imperial College Computing Student Workshop. Open Access Series in Informatics (OASIcs), Volume 35, pp. 65-72, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


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@InProceedings{lu_et_al:OASIcs.ICCSW.2013.65,
  author =	{Lu, Xin and Martin, Graham R.},
  title =	{{Fast Implementation of the Scalable Video Coding Extension of the H.264/AVC Standard}},
  booktitle =	{2013 Imperial College Computing Student Workshop},
  pages =	{65--72},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-63-7},
  ISSN =	{2190-6807},
  year =	{2013},
  volume =	{35},
  editor =	{Jones, Andrew V. and Ng, Nicholas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ICCSW.2013.65},
  URN =		{urn:nbn:de:0030-drops-42737},
  doi =		{10.4230/OASIcs.ICCSW.2013.65},
  annote =	{Keywords: Fast mode selection, Inter-layer prediction, Scalable Video Coding (SVC), SVC extension of H.264/AVC.}
}
Document
Improved Rate Control Algorithm for Scalable Video Coding

Authors: Xin Lu and Graham R. Martin

Published in: OASIcs, Volume 35, 2013 Imperial College Computing Student Workshop


Abstract
In the Scalable Video Coding (SVC) standard, a multi-layer based structure is utilised to support scalability. However in the latest Joint Scalable Video Model (JSVM) reference software, the rate control algorithm is implemented only in the base layer, and the enhancement layers are not equipped with a rate control scheme. In this work, a novel rate control algorithm is proposed for when inter-layer prediction is employed. Firstly, a Rate-Quantisation (R-Q) model, which considers the coding properties of different prediction modes, is described. Secondly, an improved Mean Absolute Difference (MAD) prediction model for the spatial enhancement layers is proposed, in which the encoding results from the base layer are used to assist the linear MAD prediction in the spatial/CGS enhancement layers. Simulation results show that, on average, rate control accuracy is maintained to within 0.07%. Compared with the default JVT-G012 rate control scheme employed in SVC, the proposed rate control algorithm achieves higher coding efficiency, namely an improvement of up to 0.26dB in PSNR and a saving of 4.66% in bitrate.

Cite as

Xin Lu and Graham R. Martin. Improved Rate Control Algorithm for Scalable Video Coding. In 2013 Imperial College Computing Student Workshop. Open Access Series in Informatics (OASIcs), Volume 35, pp. 73-80, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2013)


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@InProceedings{lu_et_al:OASIcs.ICCSW.2013.73,
  author =	{Lu, Xin and Martin, Graham R.},
  title =	{{Improved Rate Control Algorithm for Scalable Video Coding}},
  booktitle =	{2013 Imperial College Computing Student Workshop},
  pages =	{73--80},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-939897-63-7},
  ISSN =	{2190-6807},
  year =	{2013},
  volume =	{35},
  editor =	{Jones, Andrew V. and Ng, Nicholas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ICCSW.2013.73},
  URN =		{urn:nbn:de:0030-drops-42744},
  doi =		{10.4230/OASIcs.ICCSW.2013.73},
  annote =	{Keywords: Inter-layer prediction, MAD prediction, Rate control, Scalable Video Coding (SVC), SVC extension of H.264/AVC}
}
Document
Online Traveling Salesman Problems with Flexibility

Authors: Patrick Jaillet and Xin Lu

Published in: Dagstuhl Seminar Proceedings, Volume 9261, Models and Algorithms for Optimization in Logistics (2009)


Abstract
The Traveling Salesman Problem (TSP) is a well-known combinatorial optimization problem. We are concerned here with online versions of a generalization of the TSP on metric spaces where the server doesn't have to accept all requests. Associated with each request (to visit a point in the metric space) is a penalty (incurred if the request is rejected). Requests are revealed over time to a server, initially at a given origin, who must decide which requests to serve in order to minimize the time to serve all accepted requests plus the sum of the penalties associated with the rejected requests. In a first online version of this problem (basic version), we assume that the server's decision to accept or reject a request can be made any time after its release date. In a second online version of this problem (real-time version), we assume that the server's decision to accept or reject a request must be made exactly at its release date. After reviewing prior results on the online TSP, we first provide an optimal 2-competitive online algorithm for the basic version of the problem in a general metric space, improving prior results from the literature. We then consider the real-time version of the problem and show that there can't be any finite $c$-competitive online algorithm in a general metric space.

Cite as

Patrick Jaillet and Xin Lu. Online Traveling Salesman Problems with Flexibility. In Models and Algorithms for Optimization in Logistics. Dagstuhl Seminar Proceedings, Volume 9261, pp. 1-4, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)


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@InProceedings{jaillet_et_al:DagSemProc.09261.19,
  author =	{Jaillet, Patrick and Lu, Xin},
  title =	{{Online Traveling Salesman Problems with Flexibility}},
  booktitle =	{Models and Algorithms for Optimization in Logistics},
  pages =	{1--4},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2009},
  volume =	{9261},
  editor =	{Cynthia Barnhart and Uwe Clausen and Ulrich Lauther and Rolf H. M\"{o}hring},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.09261.19},
  URN =		{urn:nbn:de:0030-drops-21720},
  doi =		{10.4230/DagSemProc.09261.19},
  annote =	{Keywords: Online TSP, service flexibility, rejection options}
}
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