This work proposes a way to cut the computational load required in an algebraic codebook search, where the combined local optimal pulse method extracts the optimal pulse out of each track independently so as to form an intended codevector. Validated through ITU-T G.729A, this method is able to reduce the computational complexity remarkably while maintaining a satisfactory speech quality, compared with both the least important pulse replacement and iteration-free pulse replacement algorithms. Furthermore, the improved version of G.729A is applicable to a real-time voice over internet protocol (VoIP) system on such poor performed mobile devices.
- ACELP, Speech codec
- Algebraic codebook
- Combined local optimal pulse method