Source driven variable bit rate prototype interpolation coding
Costas S. Xydeas, Binshi Cao · 2002
Current developments in high quality, low bit rate speech coders are focused at bit rates in the region of 2.4 kbps and below. This paper presents a source driven variable bit rate coding scheme which operates in conjunction with a prototype interpolation coder (PIC). The proposed SD-VBRC-PIC coder explores effectively the residual redundancy that can be found in the evolution with time trajectories of the PIC model parameters, using a variable synthesis frame size technique. Furthermore, this approach is generic and VBRC can be applied to other prototype interpolation coding systems. Computer simulation experiments show that on average up to a maximum of 30% bit rate savings can be achieved for the same recovered speech quality, as compared to the fixed bit rate of the PIC system under consideration.