Vector Predictive Coding for Very Low-Bit-Rate Speech Encoders

The application of adaptive vector predictive coding for very low-bit-rate speech encoders was investigated and the performance quantified. The input speech samples were analyzed using the government standard LPC-10 algorithm to generate a vector with 10 LPC coefficients. This LPC vector was used as the input for vector prediction. Three prediction schemes: time-invariant prediction switched prediction and continuous prediction were investigated. The assumption of independence among the LPC coefficients was also studied. The results indicated the performance of time-invariant and independent prediction schemes is satisfactory for very-low-bit rate speech encoding applications.