LOW COMPLEX FORWARD ADAPTIVE LOSS COMPRESSION ALGORITHM AND ITS APPLICATION IN SPEECH CODING
Jelena NikoliŠ – Zoran PeriŠ – Dragan AntiŠ – Aleksandra JovanoviŠ – Dragan DeniŠ
This paper proposes a low complex forward adaptive loss compression algorithm that works on the frame by frame basis. Particularly, the algorithm we propose performs frame by frame analysis of the input speech signal, estimates and quantizes the gain within the frames in order to enable the quantization by the forward adaptive piecewise linear optimal compandor. In comparison to the solution designed according to the G.711 standard, our algorithm provides not only higher level of the average signal to quantization noise ratio, but also performs a reduction of the PCM bit rate for about 1 bits/sample. Moreover, the algorithm we propose completely satisfies the G.712 standard, since it provides overreaching the curve defined by the G.712 standard in the whole of variance range. Accordingly, we can reasonably believe that our algorithm will find its practical implementation in the high quality coding of signals, represented with less than 8 bits/sample, which as well as speech signals follow Laplacian distribution and have the time varying variances.
Keywords: forward adaptive technique, loss compression algorithm, piecewise linear optimal compandor