In this paper, SNR scalable representations of video signals are studied. The investigated codecs are well suited for communications applications because they are all based on backward motion-compensated predictive coding, which provides the necessary low-delay property. In a very-low bit rate context (VLBR), the matching pursuits (MP) signal representation algorithm is used to represent the displaced frame difference (DFD) of each layer of a multilevel decomposition of the video signal. A number of conventional prediction schemes that can be generalized to any DFD representation technique are considered. They are compared with an original and MP specific DFD prediction method. Two scenari have been considered. In the first scenario, an enhancement layer is built on a base layer that has been encoded using a classical, i.e., nonscalable scheme. In that case, all methods appear to be comparable, In the second scenario, the fact that the base layer is used as a reference for an enhancement layer is taken into account to build it. In that case, the proposed MP prediction method clearly outperforms all other conventional approaches, Additional lessons can be drawn from this work. The same motion vectors can be used in both SNR layers, and the DFD prediction between layers improves coding efficiency. Moreover, the MP representation of the signal enable us to measure the predictability of the high SNR layer DFD from the low SNR layer DFD, i.e., to quantify the part of the low SNR layer information that also belongs to the high SNR layer.

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SNR scalability based on matching pursuits

Since three-dimensional (3-D) subband coding has been introduced, most researches on 3-D subband coding perform temporal filtering first. In this paper, we investigate the best permutation strategy for temporal, vertical, and horizontal filtering to minimize the requirement of delay elements and find that the results are opposite to our expectation.

Hardware efficient design of filter banks for video coding

Analysis/synthesis filter banks designed for subband video compression

Since three-dimensional (3-D) subband coding has been introduced, most researches on 3-D subband coding perform temporal filtering first. In this paper, however, we investigate the best permutation strategy for temporal, vertical, and horizontal filtering to minimize the requirement of delay elements and find that the results are opposite to our expectation.

Design strategy for three-dimensional subband filter banks

An investigation is made on the compatibility of the video formats, standard TV (625/50/2:1/4:3), EDTV (625/50/1:1/16:9), HDTVint (1250/50/2:1/16:9) and HDTVpro (1250/50/1:1/16:9) in three-dimensional subband coding. A hierarchical method is proposed leading to a more reasonable joint solution for the issues of digital transmission evolution and interlace-to-progressive scanning conversion in the frame work of bit rate compression. Conventional HDTVint with the diamond shaped spectrum is proposed to be replaced by a kind of "switching" HDTVint signal which consists of three components and motion detection bits (MDB). The first component and the MDB represent TV. The first plus the second component and the MDB represent EDTV. HDTVpro is split into switching HDTVint and an extra component. The switching threshold and the length of temporal filter banks are discussed. Rearranging the pixels in subbands is recommended. Based on the proposed method, the transmission system can evolve through four steps: TV, EDTV, HDTVint, and HDTVpro. Results of bit rate compression are also presented. TV, EDTV, HDTVint, and HDTVpro are compressed to approximately 40, 80, 128, and 256 Mb/s, respectively. Interlace scanning has drawbacks such as line flicker and line crawling as the eye follows the line structure in the picture. Progressive version switching TV and HDTVint could be reconstructed using one frame memory without the problems of handling temporal-vertical diamond shaped spectra of conventional TV and HDTVint based on one-frame memory algorithm in the receiver. >

Weile Zhu

Papers

A method for hierarchical subband HDTV splitting