Residual-excited linear prediction

Residual-excited linear prediction (RELP) is an obsolete speech coding algorithm. It was originally proposed in the 1970s[1] and can be seen as an ancestor of code-excited linear prediction (CELP). Unlike CELP however, RELP directly transmits the residual signal. To achieve lower rates, that residual signal is usually down-sampled (e.g. to 1–2 kHz). The algorithm is hardly used anymore in audio transmission.

It is still used in some text-to-speech voices, such as the diphone databases found in the Festival and Flite speech synthesizers.[2][3]

  1. ^ Magill, D. T.; Un, C. K. (Apr 1974). "Residual excited linear predictive coder". The Journal of the Acoustical Society of America. 55 (S1): S81. Bibcode:1974ASAJ...55...81M. doi:10.1121/1.1919989.
  2. ^ "The Festival Speech Synthesis System".
  3. ^ "LPC databases (Festival Speech Synthesis System)".