Code-excited linear prediction

About: Code-excited linear prediction is a research topic. Over the lifetime, 2025 publications have been published within this topic receiving 28633 citations. The topic is also known as: CELP.

On the use of pitch predictors with high temporal resolution

Abstract: The use of pitch predictors in linear predictive coding systems is an efficient way to represent periodicity in the speech signal. Typically, the predictor is described by one parameter representing the delay in samples and 1 to 3 predictor coefficients can provide interpolation for periodicities that are not a multiple of the sampling interval and allow for a frequency-dependent gain. The authors describe a first-order pitch predictor whose delay is specified as an integer number of samples plus a fraction of a sample at the current sampling frequency. This realization has a better performance than conventional multiple coefficient predictors and leads to more efficient coding of the predictor parameters. >

Code excited linear prediction speech coding system

Abstract: A code excited linear prediction (CELP) type speech signal coding system is provided, a code vector obtained by applying linear prediction to a vector of a residual speech signal of white noise is stored in a code book. A pitch prediction vector obtained by applying linear prediction to a residual signal of a preceding frame is given a delay corresponding to a pitch frequency and added to the code vector. Use is made of an impulse vector obtained by applying linear prediction to a residual signal vector of impulses having a predetermined relationship with the vectors of the white noise code book. Variable gains are given to at least the above code vector and impulse vector, a reproduced signal is produced, and this reproduced signal is used for identification of the input speech signal. Thus, a pulse series corresponding to the sound source of voiced speech sounds is created.

Voiced, unvoiced or noise modes in a CELP vocoder

Abstract: A bit rate Codebook Excited Linear Predictor (CELP) communication system which includes a transmitter that organizes a signal containing speech into frames of 40 millisecond duration, and classifies each frame as one of three modes: voiced and stationary, unvoiced or transient, and background noise.

Low-complexity code excited linear prediction encoding

Abstract: Information about excitation signals of a first signal encoded by CELP is used to derive a limited set of candidate excitation signals for a second correlated second signal Preferably, pulse locations of the excitation signals of the first encoded signal are used for determining the set of candidate excitation signals More preferably, the pulse locations of the set of candidate excitation signals are positioned in the vicinity of the pulse locations of the excitation signals of the first encoded signal The first and second signals may be multi-channel signals of a common speech or audio signal However, the first and second signals may also be identical, whereby the coding of the second signal can be utilized for re-encoding at a lower bit rate

Combined speech and audio coding by discrimination

Abstract: We propose in this paper a general solution for combined speech and audio coding. Particularly, we describe a speech/music discrimination procedure for multi-mode wideband coding. The speech/music decision is updated only when a low-energy frame is detected, and kept unchanged otherwise. The signal is classified using second-order statistics of discriminant parameters. An experimental CELP/transform coder operating at 16 kbit/s is demonstrated. Results show improved performance when compared to single-mode encoding.