“…Unlike [2] and [3], where the quantizer models are composed of SQs with an equal number of quantization levels, the models proposed in [4,5] are composed of SQs with an unequal number of quantization levels. To provide the highest possible quality of the quantized signal, given fixed bit rate, the support region thresholds of SQs observed in [2][3][4][5] have been optimized.…”