Fast CELP coding based on algebraic codes

Adoul, J.-P.; Mabilleau, P.; Delprat, M.; Morissette, S.

doi:10.1109/icassp.1987.1169413

Cited by 128 publications

(31 citation statements)

References 5 publications

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“…The codevectors in an algebraic innovation codebook contain only few non-zero pulses while the number of the pulses depends on the bit rate of the codebook. The task of the ACELP coder is to search the pulse positions and their signs to minimize a mean square error criterion [2]. While the ACELP coder is very efficient at low bit rates, it faces some difficulties at high bit rates.…”

Section: Introductionmentioning

confidence: 99%

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Flexible and scalable transform-domain codebook for high bit rate CELP coders

Eksler

Bessette

Jelinek

et al. 2017

2017 25th European Signal Processing Conference (EUSIPCO)

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Abstract-The Code-Excited Linear Prediction (CELP) model is very efficient in coding speech at low bit rates. However, if the bit rate of the coder is increased, the CELP model does not gain in quality as quickly as other approaches. Moreover, the computational complexity of the CELP model generally increases significantly at higher bit rates. In this paper we focus on a technique that aims to overcome these limitations by means of a special transform-domain codebook within the CELP model. We show by the example of the AMR-WB codec that the CELP model with the new flexible and scalable codebook improves the quality at high bit rates at no additional complexity cost.

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Section: Introductionmentioning

confidence: 99%

“…However, in modern speech coding systems, the Algebraic CELP (ACELP) model [2] is often used. The codevectors in an algebraic innovation codebook contain only few non-zero pulses while the number of the pulses depends on the bit rate of the codebook.…”

Section: Introductionmentioning

confidence: 99%

Flexible and scalable transform-domain codebook for high bit rate CELP coders

Eksler

Bessette

Jelinek

et al. 2017

2017 25th European Signal Processing Conference (EUSIPCO)

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“…Such vectors can be represented in various ways. For example, in widely deployed algebraic CELP (ACELP) [4], the pre-fixed vectors are generated by combining some unit pulses located at pre-determined positions. The CED is performed using both ACB and FCB vectors.…”

Section: Introductionmentioning

confidence: 99%

Corrupted encoded data detection for a CELP decoder

2017

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Undetectable data corruption in wireless communication links can occur in some cases, including cases in which a ciphering algorithm can fail to generate the same keystream for encryption at a receiver side as it does for a sender side. In wireless speech communication, such corruption might trigger an explosion of decoded sound, which might in turn hurt a user's ear. This article presents a simple algorithm for detecting corruption for a typical code-excited linear-prediction (CELP) speech decoder. The algorithm requires no additional bits for corruption detection, but detects it by monitoring the amplitude ratio of decoded adaptive and fixed excitation signals in CELP. Its practicality is demonstrated by simulation.

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“…An algebraic code-excited linear prediction (ACELP)-based speech coding technique [1][2][3] is a type of technique most widely applied to digital speech communication systems and serves as a mainstream technique adopted in a great number of speech coding standards due to a double advantage of low bit rates and high speech quality. The main coding flow for an ACELP coding technique is to perform a linear predictive coding (LPC) on an input speech signal and then perform an adaptive as well as an algebraic codebook search on an LPC residual signal.…”

Section: Introductionmentioning

confidence: 99%

An efficient algebraic codebook search for ACELP speech coder

Yeh

Hwang

2014

J AUDIO SPEECH MUSIC PROC.

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In a bid to enhance the search performance, this paper presents an improved version of reduced candidate mechanism (RCM), an algebraic codebook search conducted on an algebraic code-excited linear prediction (ACELP) speech coder. This improvement is made based on two findings in a piece of our prior work. The first finding is that a pulse with a high contribution in the associated track is more likely to serve as an optimal pulse in the optimal codevector and the second is that the speech quality can be well maintained at a search accuracy above 50% approximately. Subsequently, a new finding in this study concerning a structured algebraic codebook in G.729 indicates that there is a 0.8321 probability that the number 1 ranked pulse in a global sorting by pulse contribution is indeed one of the optimal pulses. Hence, the number 1 pulse in the global sorting is labeled as one of the optimal pulses, following which a sequence of search tasks are fulfilled through RCM. This proposed complexity reduction algorithm, implemented on a G.729A speech codec, takes as few as eight searches, a search load tantamount to 2.5% of G.729A, 12.5% of global pulse replacement method (iteration = 2), 16.7% of iteration-free pulse replacement method, and 50% of RCM (N = 2). This proposal is thus found to successfully reduce the required computational complexity to a great extent as intended.

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Fast CELP coding based on algebraic codes

Cited by 128 publications

References 5 publications

Flexible and scalable transform-domain codebook for high bit rate CELP coders

Flexible and scalable transform-domain codebook for high bit rate CELP coders

Corrupted encoded data detection for a CELP decoder

An efficient algebraic codebook search for ACELP speech coder

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