Low Bit Rate Coding with Binary Golay Codes
چکیده
Even if the computational power is constantly increasing, as well as the storage resources, the type and quantity of data stored and exchanged over the communication channels is expanding. Multimedia communication becomes an everyday aspect of our lives, and with it our expectations relative to the quality of both the communication and content are raising. From the content coding point of view, these aspects are reflected in the continuous need of low bit-rate compression algorithms that have a good compression performance and low complexity. Within the lossy compression methods, the lattice based quantization tools have gained some momentum, being present in several state of the art speech and audio codecs such as AMR-WB+ [1], G.718 [2], G.729.1 [3]. However, due to the wide range of terminals there is a general tendency towards bit rate embedded scalability of the codecs. In the speech and audio coding context, where most of the bits are allocated to transform coefficients, or to differential transform coefficients, the bit rate of interest to encode this data is around 0.5 bits per sample (bps). Recently [4], the binary codes have been shown to perform well as tools for quantization at low bit rates. In particular, the perfect Golay codes G23 have been used within a quantization method for outlier contaminated sources and tested within a speech and audio coding scenario. The method has been demonstrated to be superior to state of the art method based on lattices, in terms of compression efficiency, but the complexity requirements were still relatively high. Further method refinement and improvement [5] have been aimed at and achieved important complexity reduction while preserving the same compression performance. This presentation aims at giving a unified view over the Golay code based coding as described in [4], [5] and [6]. We will thus briefly describe the original method, followed by the techniques of complexity reduction and overall results.