Qian Xu

Publications (5)0 Total impact

• Conference Proceeding: Directional adaptive loop filter for video coding.

  Yunfei Zheng, Peng Yin, Qian Xu, Joel Solé, Xiaoan Lu
  18th IEEE International Conference on Image Processing, ICIP 2011, Brussels, Belgium, September 11-14, 2011; 01/2011
• Conference Proceeding: Classified quadtree-based adaptive loop filter.

  Qian Chen, Yunfei Zheng, Peng Yin, Xiaoan Lu, Joel Solé, Qian Xu, Edouard François, Dapeng Wu
  Proceedings of the 2011 IEEE International Conference on Multimedia and Expo, ICME 2011, 11-15 July, 2011, Barcelona, Catalonia, Spain; 01/2011
• Conference Proceeding: Adaptive motion vector resolution with implicit signaling

  Liwei Guo, Peng Yin, Yunfei Zheng, Xiaoan Lu, Qian Xu, J. Sole
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  ABSTRACT: In all video coding standards, motion vectors are restricted to have the same resolution for the whole sequence. In this paper, we propose an adaptive motion vector resolution scheme to improve the coding efficiency. The scheme is based on an analytical model of motion compensated residue which studies the relationship between motion vector errors and the variance of the residue. With this model, the proposed scheme can adaptively select motion vector resolution with implicit signaling. Experimental results show that the proposed scheme can improve coding efficiency at slightly increased encoding complexity.
  Image Processing (ICIP), 2010 17th IEEE International Conference on; 10/2010
• Conference Proceeding: Coupled pre-/post-processing filters for predictive video coding

  K. Misra, J. Sole, Xiaoan Lu, Peng Yin, Yunfei Zheng, Qian Xu
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  ABSTRACT: Pre-/post-processing filters obtained from lapped transforms achieve higher coding efficiency by exploiting transform block boundary correlation. Existing approaches however do not explicitly consider the impact of pre-filtering on prediction efficiency, thereby resulting in a lower overall rate-distortion performance. We present a framework where filters are designed with an objective function based on a prediction model. The post-filter is constructed so as to reverse the pre-filter processing at the decoder. We show how the pre-filters thus derived can be refined and local adaptation parameters obtained for better compression efficiency. To further enhance the performance, the mode decision is altered by separating the contribution of luma and chroma components in the rate-distortion model. The overall system performance is measured using a weighted Bjontegaard delta bitrate, showing an overall saving of 2.58% to 6.78% with respect to the “Key Technical Area” (KTA) codec. Additionally, the designed filters significantly reduce the blocking artifacts observed in KTA.
  Image Processing (ICIP), 2010 17th IEEE International Conference on; 10/2010
• Source

  Available from: technion.ac.il

  Conference Proceeding: Simplified geometry-adaptive block partitioning for video coding.

  Liwei Guo, Peng Yin, Yunfei Zheng, Xiaoan Lu, Qian Xu, Joel Solé
  Proceedings of the International Conference on Image Processing, ICIP 2010, September 26-29, Hong Kong, China; 01/2010