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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17 May 1995
TL;DR: In this article, the robustness of the linear prediction whose minimization process is based on a least absolute error criterion is discussed, and it is shown that a pole-zero model of speech signals can approximate better the spectral envelope compared to that obtained by traditional linear prediction.
Abstract: This paper discusses the robustness of the linear prediction whose minimization process is based on a least absolute error criterion. Due to such robustness in the preciseness of prediction, we can estimate a pole-zero model of speech signals and approximate better the spectral envelope compared to that obtained by traditional linear prediction.
3 citations
Patent•
16 Aug 2001
TL;DR: In this article, a method for searching a codebook CELP type vocoder is provided to reduce the searching time for easily realizing the vocoder with chip DSPs and to add other functions into the device as many as the reduced calculation amount, and thereby efficiently designing the system.
Abstract: PURPOSE: A method for searching a code-book CELP type vocoder is provided to reduce the searching time for easily realizing the vocoder with chip DSPs(Digital Signal Processors) and to add other functions into the device as many as the reduced calculation amount, and thereby efficiently designing the system. CONSTITUTION: A signal x(n), in which long/short term prediction components is removed from an original input voice signal, is outputted through a weighting filter and used as an input voice for searching a code-book. That is, a correlativity(Exy and Eyy) is obtained by using the input signal x(n) and synthetic voice(y1(n)) made by filtering a code vector for a present code-book index value through a pitch synthetic filter and a formant synthetic filter. And, a minimum error value is obtained by using the correlativity(Exy and Eyy) and a fixed code-book gain value(G). Then, the searching operation is finished after outputting a currently selected code-book index and the gain, if the times for searching the minimum error are exceeded over a predetermined minimum error counter value.
3 citations
Patent•
17 Aug 2004TL;DR: In this paper, two prediction and coding schemes for video coding are presented. But they employ prediction across spatial scales and coding across different orientation sub-bands, respectively, to optimize the rate, distortion, and complexity simultaneously.
Abstract: Several prediction and coding schemes are combined to optimize performance in terms of the rate-distortion-complexity tradeoffs. Certain schemes for temporal prediction and coding of Motion Vectors (MVs) are combined with a new coding paradigm of over complete wavelet video coding. Two prediction and coding schemes are set forth herein. A first prediction and coding scheme employs prediction across spatial scales. A second prediction and coding scheme employs a motion vector prediction and coding across different orientation sub-bands. A video coding scheme utilizes joint prediction and coding to optimize the rate, distortion and the complexity simultaneously.
3 citations
TL;DR: A convenient selection of parameters and an optimum strategy for quantizing prediction coefficients are put forth, which reduce transmission rate to less than 3 bits/pel while ensuring exact reproduction of the source.
3 citations
23 Mar 1992
TL;DR: A transformed codebook approach is proposed and it is shown that several well-known CELP schemes can be formulated in this way, and comparative results are given for different transformation matrices.
Abstract: The authors deal with the design and efficient codebooks in terms of quality and complexity for code excited linear prediction (CELP) coding of speech. For this purpose, a transformed codebook approach is proposed and it is shown that several well-known CELP schemes can be formulated in this way. Comparative results are given for different transformation matrices, including a new method called fractional excitations. Another technique based on singular value decomposition (SVD) of the impulse response matrix is introduced. In this technique an innovation sequence appears as a linear combination of a set of eigenvectors with optimally vector quantized coefficients. Preliminary results are presented for this new SVD-CELP technique. The authors describe a multi-codebook approach which enabled a significant bit rate reduction of the speech coder submitted to GSM half rate standardization. >
3 citations