Patent ID: 6122608
Filing Date: 2000-09-19
Classification: G10L

Abstract:
A switched predictive method of quantizing an input signal comprising the steps of:generating a set of parameters associated with said input signal;providing a first mean value and subtracting said first mean value from said set of parameters to get first mean-removed input;providing a second mean value and subtracting said second mean value from said set of parameters to get second mean-removed input;providing a quantizer with a first set of codebooks and second set of codebooks;providing a first prediction matrix and a second prediction matrix;multiplying a previous frame mean-removed quantized value to said first prediction matrix then said second prediction matrix to get first predicted value and then second predicted value;subtracting said first predicted value from said first mean-removed input to get first target value and subtracting said second predicted value from said second mean-removed input to get second target value;applying said first target value to said first set of codebooks to get first quantized target value and applying said second target value to said second set of codebooks to get second quantized target value;adding said first predicted value to said first quantized target value to get first mean-removed quantized value and adding said second predicted value to said second quantized target value to get second mean-removed quantized value;adding said first mean value to said first mean-removed quantized value to get first quantized value and adding said second mean value to said second mean-removed quantized value to get second quantized value; anddetermining which set of codebooks and prediction matrix has minimum error and selectively providing an output signal representing the quantized value corresponding to that codebook set with minimum error.