Low bit rate speech coding

This paper describes the objective of speech coding to achieve toll quality performance at minimum bit rate and to improve the efficiency of transmission and storage, reduce cost, increase security and robustness in transmission. Speech coding can be achieved based on two facts: redundancy in speech signals, and the perception properties of human ears. Performance evaluation of speech coding is obtained by speech quality, coding rate, algorithm complexity and delay. The two speech coding methods: waveform coding and parametric coding uses a synthetic model for speech analysis and reconstruction. This paper focuses on a source coding and subjective mean opinion score methods are used to measure the speech perception based on score given by the listener to achieve low bit rate coding.