Speech Coding at very low rate

This work is an introduction to research in the field of speech coding. The goal is to become familiar with the latest technical analysis and speech coding to get the developing of two coders operating at very low speed, respectively (2400 and 1200 bps). The choice of the encoding algorithm has been focused on the MELP (Mixed Excitation Linear Prediction), which has a flow rate ratio / interesting quality. Several versions of the MELP exist, but they are in a fixed form and whose development or the improvement is not adequate for research work of this team. In order to have a modular and customized version. Firstly, we develop a MATLAB objectives MELP coder operating at 2.4 and 1.2 kbps and whose modules can be easily changed. Subsequently, we made a number of changes to the basic algorithm for the purpose of improvement and adaptation to applications being developed in the laboratory. Secondly, we reduce the flow; develop and transmit voice over IP; combat packet loss during the transmission. Keywords— Speech coding, LPC coding, MELP vocoder.