Layer Selection in Progressive Transmission of Motion-Compensated JPEG2000 Video

MCJ2K (Motion-Compensated JPEG2000) is a video codec based on MCTF (Motion- Compensated Temporal Filtering) and J2K (JPEG2000). MCTF analyzes a sequence of images, generating a collection of temporal sub-bands, which are compressed with J2K. The R/D (Rate-Distortion) performance in MCJ2K is better than the MJ2K (Motion JPEG2000) extension, especially if there is a high level of temporal redundancy. MCJ2K codestreams can be served by standard JPIP (J2K Interactive Protocol) servers, thanks to the use of only J2K standard file formats. In bandwidth-constrained scenarios, an important issue in MCJ2K is determining the amount of data of each temporal sub-band that must be transmitted to maximize the quality of the reconstructions at the client side. To solve this problem, we have proposed two rate-allocation algorithms which provide reconstructions that are progressive in quality. The first, OSLA (Optimized Sub-band Layers Allocation), determines the best progression of quality layers, but is computationally expensive. The second, ESLA (Estimated-Slope sub-band Layers Allocation), is sub-optimal in most cases, but much faster and more convenient for real-time streaming scenarios. An experimental comparison shows that even when a straightforward motion compensation scheme is used, the R/D performance of MCJ2K competitive is compared not only to MJ2K, but also with respect to other standard scalable video codecs

State-of-the-Art and Trends in Scalable Video Compression with Wavelet Based Approaches

3noScalable Video Coding (SVC) differs form traditional single point approaches mainly because it allows to encode in a unique bit stream several working points corresponding to different quality, picture size and frame rate. This work describes the current state-of-the-art in SVC, focusing on wavelet based motion-compensated approaches (WSVC). It reviews individual components that have been designed to address the problem over the years and how such components are typically combined to achieve meaningful WSVC architectures. Coding schemes which mainly differ from the space-time order in which the wavelet transforms operate are here compared, discussing strengths and weaknesses of the resulting implementations. An evaluation of the achievable coding performances is provided considering the reference architectures studied and developed by ISO/MPEG in its exploration on WSVC. The paper also attempts to draw a list of major differences between wavelet based solutions and the SVC standard jointly targeted by ITU and ISO/MPEG. A major emphasis is devoted to a promising WSVC solution, named STP-tool, which presents architectural similarities with respect to the SVC standard. The paper ends drawing some evolution trends for WSVC systems and giving insights on video coding applications which could benefit by a wavelet based approach.partially_openpartially_openADAMI N; SIGNORONI. A; R. LEONARDIAdami, Nicola; Signoroni, Alberto; Leonardi, Riccard

New prediction schemes for scalable wavelet video coding

A Scalable Video Coder (SVC) can be conceived according to different kinds of spatio-temporal decomposition structures which can be designed to produce a multiresolution spatio-temporal subband hierarchy which is then coded with a progressive or quality scalable coding technique [1-5]. A classification of SVC architectures has been suggested by the MPEG Ad-Hoc Group on SVC [6]. The so called t+2D schemes (one example is [2]) performs first an MCTF, producing temporal subband frames, then the spatial DWT is applied on each one of these frames. Alternatively, in a 2D+t scheme (one example is [7]), a spatial DWT is applied first to each video frame and then MCTF is made on spatial subbands. A third approach named 2D+t+2D uses a first stage DWT to produce reference video sequences at various resolutions; t+2D transforms are then performed on each resolution level of the obtained spatial pyramid. Each scheme has evidenced its pros and cons [8,9] in terms of coding performance. From a theoretical point of view, the critical aspects of the above SVC scheme mainly reside: i) in the coherence and trustworthiness of the motion estimation at various scales (especially for t+2D schemes); ii) in the difficulties to compensate for the shift-variant nature of the wavelet transform (especially for 2D+t schemes); iii) in the performance of inter-scale prediction (ISP) mechanisms (especially for 2D+t+2D schemes). In this document we recall the STool scheme principles, already presented in [10]. We present an STool SVC architecture and compare it with respect other SVC schemes. Some main advancements and new solutions are detailed and the related results presented. Our software implementations are based on the VidWav reference software [11,12]