Topic
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.
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01 Jan 1995
TL;DR: The results show thatTCVQ performs significantly better than VQ, with reasonable complexity, which makes TCVQ a fair choice for trading quality against complexity and/or delay.
Abstract: We analyze the performance of a CELP coder where the vector quantization (VQ) of the excitation is replaced with trellis-coded vector quantization (TCVQ). Our results show that TCVQ performs significantly better than VQ, with reasonable complexity. This makes TCVQ a fair choice for trading quality against complexity and/or delay. We describe a systematic pro- cedure to replace VQ with TCVQ for existing CELP coders. We propose an optimization algorithm to appropriately populate the trellis. We show how pseudo-Gray coding (22) can be applied to the TCVQ codebook to improve intrinsic coder robustness to channel errors. Finally, we evaluate the complexity and perfor- mance of the method.
27 Mar 2000
TL;DR: A progressive transmission approach with VQ 2-D-CELP of video over fading channels approach that extends the concept of CELP for speech coding and an inverse error predictor filter, an iterative clustering method to design the predictors form an initial array and an algorithm to determine the block size are discussed.
Abstract: The problem of data transmission in a heterogeneous network environment involves many considerations, among these: the design and selection of coding schemes and transmissions techniques are the most relevant. Recently, the interest in mobile multimedia networks has stimulated the researches in this field. Significant progress has been made in this technology. The problem becomes more relevant if we desire to transmit signal in wireline and wireless networks. Progressive transmission is very useful for sending video and, in general, multimedia data over band-limited channels; although it presents problems over noisy channels due to it uses variable length coding. So it requires high quality methods to avoid channels noises.One approach is to merge the above-mentioned progressive transmission with VQ 2-D-CELP of video over fading channels approach that extends the concept of CELP for Speech Coding. This technique employs an inverse error predictor filter, an iterative clustering method to design the predictor's form an initial array and an algorithm to determine the block size. We state the general design problem, decompose it into simpler sub-problems and discuss the solutions to these sub-problems.
01 Jan 2007
TL;DR: Conjugate-Structure Algebraic CELP (G.729) is a novel approach to partitioning type ofvoice codecthat compresses speech signal that helps in further growth in communication systems.
Abstract: furthergrowthin communication systems. Conjugate-Structure Algebraic CELP(G.729) isa Meanwhile themethodsofoptimum partitioning typeofvoice codecthat compresses speech signalbecameimportant asachallenge inco-design. Some based onmodelparameters ofhumanvoice. Fullygeneral rules havebeendeveloped based on time independency (parallelism) andcalculations mass[4,
01 Jan 2013
TL;DR: It has been proved that the speech quality will be slightly degraded when using Arabic and the quality is decreased as the compression ratio increased which will be lower and unstable for Arabic or Cairo accent.
Abstract: The newly developed Code Excited Linear Prediction "CELP" Speech coders combine low data rates and good speech quality. However these coders have been built initially for 7 languages not included Arabic language. So what is the effect of the change of the spoken language or accent? This paper answers on many questions. The first question is; what is the effect of the language or accents on CELP coders? Moreover what will happen if the speech is compressed more by lower data rate coder and at the same time the language is other than English? Finally; what is the defective part in the coder? Extensive testing is done on 3 coders ITU G.711, ITU G.723.1 and 3GPP AMR. The outputs were compared with the ITU PESQ algorithm. It has been proved that the speech quality will be slightly degraded when using Arabic. Also the quality is decreased as the compression ratio increased which will be lower and unstable for Arabic or Cairo accent. Finally it is found that the main problem is the Linear Prediction vector quantization CodeBook and has been verified by the MFCC and LBG algorithm.
11 Apr 1989
TL;DR: CELP coding is a mature technique able to yield high-quality synthetic speech with some background noise at the mid-rate range, and has a tractable computational complexity and good robustness, making it the best present candidate.
Abstract: The authors present the results of a feasibility study comparing two basic classes of coders in the mid-rate range (6-8 kbps): CELP and sinusoid based coders. It is concluded that CELP coding is a mature technique able to yield high-quality synthetic speech with some background noise at the mid-rate range. It has a tractable computational complexity and good robustness, making it the best present candidate. Postprocessing can enhance its output quality, though further research is needed in this field. Sinusoidal coding, together with the use of narrowband basis functions, can produce synthetic speech of higher quality than that produced by CELP. Its robustness however, must be increased. This work suggests that a significant research effort into this technique is fully justified. >