Advanced motion vector coding framework for multiview video sequences

The inconsistency between the temporal motion vector and the disparity vector fields causes a drastic loss in coding performance during multiview video coding. In order to resolve this inconsistency problem, we investigate a new approach for motion vector coding. In this paper, degradation in accuracy using a conventional method is experimentally analyzed using mathematical tools. Then, we introduce a new framework for motion vector coding, including modified Inter-mode and Adaptive Direct-mode, in which an advanced motion vector prediction method is employed. The main idea of the proposed motion vector prediction method is to separate each motion vector field from the others. For this purpose, we introduce three alternative motion vectors; a virtual disparity vector, a virtual temporal motion vector and a scaled motion vector. The experimental results show that the proposed method can resolve the inconsistency problem and consequently improve the overall rate-distortion performance. The average bit-rate savings is about 7.3% compared to JMVC 6.0. At maximum, the gain obtained is about 20%, corresponding to a PSNR of 1.42 dB.