Coding Algorithm Based on Loss Compression using Scalar Quantization Switching Technique and Logarithmic Companding

摘要

This paper proposes a novel coding algorithm based on loss compression using scalar quantization switching technique. The algorithm of switching is performed by the estimating input variance and further coding with Nonuniform Switched Scalar Compandor (NSSC). An accurate estimation of the input signal variance is needed when finding the best compressor function for a compandor implementation. It enables quantizers to be adapted to the maximal amplitudes of input signals. Additionally, we have discussed the performances of coding schemes designed according to waveform G.711 and G.712 standards and a novel presented codec standard for wideband speech and audio coding. We have pointed out the benefits that can be achieved by using our algorithm: raise of quality and compression. The main contribution of this model is reaching the loss compression through reaching the higher quality of the signal-to-quantization noise ratio (SQNR) in a wide range of signal volumes (variances) with respect to the necessary robustness over a broad range of input variances, and applying possibility for VOIP applications and an effective coding of signals that likewise speech signals follow Gaussian distribution and have the time varying characteristics.