The existing and standardized solutions for spatial scalability are not satisfactory, therefore new approaches are very actively explored recently. The goal of this paper is to improve spatial scalability of MPEG-2 for progressive video. In order to avoid problems with too large bitstreams of the base layer produced by some of the hitherto proposed spatially scalable coders, spatio-temporal scalability is proposed for video compression systems. It is assumed that a coder produces two bitstreams, where the base-layer bitstream corresponds to pictures with reduced both spatial and temporal resolution while the enhancement layer bitstream is used to transmit the information needed to retrieve images with full spatial and temporal resolution. In the base layer, temporal resolution reduction is obtained by B-frame data partitioning, i.e., by placing each second frame (B-frame) in the enhancement layer. Subband (wavelet) analysis is used to provide spatial decomposition of the signal. Full compatibility with the MPEG-2 standard is ensured in the base layer. As compared to single-layer MPEG-2 encoding at bit rates below 6 Mbits/s, the bitrate overhead for scalability is less than 15% in most cases.Index Terms-MPEG-2, spatial scalability, subband analysis, temporal scalability, video coding.
We deal with the processing of multiview video acquired by the use of practical thus relatively simple acquisition systems that have a limited number of cameras located around a scene on independent tripods. The real-camera locations are nearly arbitrary as it would be required in the real-world FreeViewpoint Television systems. The appropriate test video sequences are also reported. We describe a family of original extensions and adaptations of the multiview video processing algorithms adapted to arbitrary camera positions around a scene. The techniques constitute the video processing chain for FreeViewpoint Television as they are aimed at estimating the parameters of such a multi-camera system, video correction, depth estimation and virtual view synthesis. Moreover, we demonstrate the need for new compression technology capable of efficient compression of sparse convergent views. The experimental results for processing the proposed test sequences are reported.
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