Effiziente sehr niederratige Sprachübertragung mittels Interblock-Codierung

Abstract

The article presents a new data compression scheme for very-low-rate speech coding at 1000 b/s and below. The method which is called matrix product quantization (MPQ) encodes matrices containing successive LPC parameter vectors by a product formulation of two matrices which describe the average parameter vector and the temporal parameter contour. MPQ can be applied in fixed rate as well as in variable rate coding systems. At a fixed bit rate MPQ yields a very high coding efficiency at relatively low coding delay and medium complexity. Applied in a variable rate segment vocoder MPQ achieves even higher compression gains at the cost of increased coding delay and complexity. In general, it is shown that interblock coding, which is made by MPQ, considerably outperforms memoryless coding. In a particular comparison to interpolative coding methods which is often used for very-low-rate speech coding, MPQ is clearly superior since only MPQ is able to exactly model the temporal parameter contour.