Multiple source MOS evaluation of a flexible low-rate vocoder

This paper describes the design and MOS (mean opinion score) performance of a family of low rate, low complexity speech coding algorithms known as time domain voicing cutoff (TDVC). TDVC is a predictive coding algorithm that employs a single transition frequency dividing voiced and unvoiced excitation. It provides the voicing flexibility of a frequency domain algorithm with lower complexity and rate overhead. A number of algorithm variants were MOS tested using three distinct sets of source material. The results are discussed in terms of performance for each of the three sources, and demonstrate that choice of source material has a great impact on both vocoder scoring and ranking