Extending SVC by Content-adaptive Spatial Scalability
This paper provides details on a complete integration of Content-adaptive Spatial Scalability (CASS) into the scalable video coding extension of H.264/AVC (SVC). CASS enables the efficient encoding of a high-quality bit stream that contains several versions of an original image sequence. Thereby, each such image sequence has been created by content-adaptive and art directed retargeting to different display aspect-ratios and/or resolutions. Non-linear dependencies between spatial layers, which have been introduced through content-adaptive retargeting, are exploited by a generalization of the three inter-layer prediction tools of SVC, i.e. by content-adaptive inter-layer texture, motion and residual prediction. The CASS extended SVC enables the transmission of video content which has been specifically adapted in an art-directed way to multiple display configurations (e.g. to SD and HD displays with 4:3 and 16:9 aspect-ratios, respectively) using a single compressed bit stream. With our extension, video content of higher semantic quality can be transmitted in a scalable way by introducing an average overhead in bit rate of 9.3%.