Extended spatial scalability for non dyadic video formats: from SDTV to HDTV
Gwenaëlle Marquant, Édouard François, Nicolas Burdin, Patrick Lopez, Jérôme Viéron · 2005
High Definition Television is currently a hot topic that generates research and commercial interests in video industry. This paper relates to video coding devices and methods for easy and fast conversion of video formats for digital TV. The proposed algorithm provides a generic framework that allows any video format conversions in a scalable way. We focused particularly on solutions to extract Standard Definition video signals from High Definition ones. Practically, we address spatial scalability solutions between video formats that are not linked up by dyadic decomposition and/or istropic decomposition. The challenge is to generate a single scalable bitstream in a compliant way that permits any spatial resolution decodings while saving bandwidth compared to classical simulcast approaches. Practically, our scalable coder is based on a multi-layer approach and on frame scales and borders introduction. Moreover, to encode/decode the macroblocks of the high resolution pictures, usual video coding approaches exploit the inheritance knowing the macroblocks of the decoded low resolution pictures. Approaches for inter-layer prediction of motion data have already been proposed for dyadic decompositions but do not work in case of non dyadic inter-layer resolutions. Consequently we propose a different managing of the inter layer prediction. All these techniques have been successfully implemented in the MPEG-SVC reference software. Obtained results achieve good coding efficiency and are comparable to the simulcast state of the art while providing features induced by scalability.