Hybrid speech coding and system

• US 20050065788A1
• Filed: 01/30/2004
• Published: 03/24/2005
• Est. Priority Date: 09/22/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Stachurski, Jacek
• Granted Patent: US 7,363,219 B2
• Time in Patent Office: Days
• US Class Current: 704/229
• CPC Class Codes: G10L 19/20 using sound class specific coding, hybrid encoders or object based coding

Abstract

Hybrid linear predictive speech coding system with phase alignment predictive quantization zero phase alignment of speech prior to waveform coding aligns synthesized speech frames of a waveform coder with frames synthesized with a parametric coder. Inter-frame interpolation of LP coefficients suppresses artifacts in resultant synthesized speech frames.

Claims

1. A method of encoding speech filter coefficients, comprising:

(a) indexing all distributions of P signed pulses on N positions by ordering said distributions in terms of number of distributions of Q pulses on M positions for Q less than P, M less than or equal to N, and without regard to the sign of any pulses at the Mth position, where P, N, Q, and M are non-negative integers.

2. The method of claim 1, wherein:

(a) each of said N positions containing at least one of said P pulses corresponds to said numbers of distributions of Q pulses on M positions for a single value of Q.

3. The method of claim 1, wherein:

(a) computing a codebook index for a distribution of P signed pulses on N positions by summing a pulse index for each non-overlapping pulse with each said pulse index a sum of terms XK(M,Q) where X is a multiplier equal to 0, 1, or 2 and K(M,Q) is the numbers of distributions of Q signed pulses on M positions without regard to the sign of any pulses at the Mth position, where P, N, Q, and M are non-negative integers.

4. The method of claim 1, wherein:

(a) providing a codebook index I_CB where I_CB is a sum of one or more pulse indexes with each pulse index corresponding to a position occupied by one or more pulses of a distribution of P signed pulses on N positions, wherein each pulse index is a sum with respect to M of one or more terms XK(M,Q) where X is a multiplier equal to 0, 1, or 2 and K(M,Q) is the number of distributions of Q signed pulses on M positions without regard to the sign of any pulses at the Mth position, and wherein P, N, Q, and M are non-negative integers;

(b) computing a distribution of P signed pulses on N positions from said codebook index I_CB by successively extracting each of said pulse indexes from I_CB where a pulse index is computed by accumulating XK(M,Q) for M decreasing from a location determined by the extraciton of the immediately prior pulse index, said accumulating continuing ultil equaling or exceeding I_CB minus the prior extracted pulse indexes.