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.

The Equivalence of ADPCM and CELP Coding

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Application of Stochastic Coding Schemes in Satellite Communication

Abstract: As digital communication has become an increasingly important field, a great deal of research is concentrated on developing new applications. Of these, low bit rate speech coding for mobile communication is of special interest. Particularly the Code Excited Linear Predictive (CELP) coders [11] have shown considerable promise in giving high quality speech at the required bit rates. The majority of the proposed coder candidates, however, are considered in the absence of a realistic channel. This paper will describe a possible speech coder candidate for Mobile Satellite Communication, the Self Excited Stochastic Multipulse (SESTMP) coder [2, 7] with a 7.0 kbit/s bit rate, taking into consideration the special features of a satellite channel.

A new bandwidth extension technology for MPEG Unified Speech and Audio Coding

Abstract: In January 2012, MPEG finalized the new MPEG-D Unified Speech and Audio Coding (USAC) standard, which enables the coding of a variety of audio content at low bitrates. USAC provides low-bitrate coding by integrating a speech codec and an audio codec into a unified system. In USAC, Predictive Vector Coding (PVC) is added to Enhanced Spectral Band Replication (eSBR) to improve the subjective quality, especially for speech at low bitrates. For speech signals, there is generally a relatively high correlation between the spectral envelopes of low- and high-frequency bands. The PVC scheme exploits this by predicting the high-frequency envelopes from the low-frequency ones, with the coefficient matrices for the prediction being coded by means of vector quantization.

Efficient techniques for determining and encoding the long term predictor lags for analysis·by· synthesis speech coders

Abstract: Many analysis-by-synthesis speech coders, such as CELP coders, make use of a combination of long-term and short-term predictors. The use of long term predictors (adaptive codebooks) incorporating lags with sub-sample resolution has contributed to enhanced performance for these coders, particularly for high pitched speakers [1], [2]. This paper discusses an efficient technique for determining the lag for the long-term predictor (index of the adaptive codebook) when sub-sample resolution lags are allowed. Also, an efficient technique for encoding these lags (adaptive codebook indices) is presented.

Implementation of a low delay modified CELP coder at 4.8 kb/s

Abstract: This paper presents a low delay high quality speech coder at low bit rates. The configuration of the speech coder is mainly composed of a formant filter, a pitch codebook, an excitation joint codebook, and post enhancement filters. The algorithm of the speech coder is briefly described. Two versions of the speech coder have been implemented in real-time with a single: ADSP-21020 chip. Both objective measurement and informal subjective listening tests show that the proposed speech coder has high quality performance.