Leaping frame detection and processing with a 2.4 kb/s SELP vocoder
Tang Kun · Journal of Tsinghua University(Science and Technology) · 2009
During the transition from an unvoiced frame to a voiced frame,the quality of the synthesized speech is not satisfactory in the SELP 2.4 kb/s speech coding algorithm.A leaping frame detection and processing method was developed to overcome this problem using the redundancy of the quantized sub-band UV(unvoiced/voiced) parameters.In this algorithm,the leaping frame is identified based on the average energy ratio of the first and last sixty samples and expressed by the redundant mode of the quantized sub-band UV parameters.The decoding process uses various interpolation methods depending on whether a leaping frame is detected.Simulations show that the algorithm significantly improves the synthesized speech quality.