A Video Encoder Based on Generalized Bit-Planes

Rogério Caetano; Eduardo A. B. da Silva; Alexandre G. Ciancio

doi:10.14209/its.2002.505

A Video Encoder Based on Generalized Bit-Planes

Rogério Caetano, Eduardo A. B. da Silva, Alexandre G. Ciancio

DOI: 10.14209/its.2002.505

Evento: 2002 International Telecommunications Symposium (ITS2002)

Keywords:

Abstract

"Among the best performing video coding methods are the ones based on the matching pursuits algorithm. In them, the motion compensated frame difference is decomposed on an overcomplete dictionary of atoms in a greedy fashion. It is represented by a sequence of pairs specifying the atoms used and their corresponding coefficients. The rate distortion trade-off is achieved by varying both the number of atoms and how the coefficients are quantized. Several strategies have been presented in order to solve the problem of, given a target rate or distortion, determining the optimum number of atoms as well as the quantizers of the corresponding coefficients. In this paper we propose a novel method for performing matching pursuits quantization, based on the notion of decomposition in generalized bit-planes. The structure of such decompositions is such that once the decomposition is carried out, it is already quantized, and there is no need to set up any quantization parameters. It does so by generating a decomposition that is readily organized in bit-planes. It provides an elegant solution to the trade-off between quantization of coefficients and number of passes in the matching pursuits algorithm. In fact, we show that it can be regarded as a generalization of any decomposition on a dictionary followed by linear quantization of the coefficients. In addition, we present a theorem that sets bounds for the R-D performance of such generalized decompositions. We test the effectiveness of the proposed method using the framework of Neff and Zakhor\u2019s matching pursuits video encoder. The results obtained are promising, presenting, without any ad-hoc assumptions about the R-D behavior of the coded frames or any increase in computational complexity, a significant improvement over the classical matching pursuits video coders. Also, the results are as good as the ones obtained employing more sophisticated strategies."

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