Code-Excited Linear Prediction, CELP

This is a linear predictive speech coding algorithm, developed in 1985. It was highly efficient and provided significantly better quality than previous low-bit-rate algorithms such as residual-excited linear prediction (RELP) and linear predictive coding (LPC) vocoders. Along with its variants, including algebraic CELP, relaxed CELP, low-delay CELP and vector sum excited linear prediction, it remains one of the most widely used speech coding algorithms today. It is also used in MPEG-4 Audio speech coding. The term CELP is often used broadly to refer to a group of algorithms rather than a specific codec.