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.

Narrowband CELP hiding by wideband speech

Abstract: We introduce in this work a framework for speech-in-speech hiding for the purpose of reducing the storage and transmission overhead in electronic voice mail applications, as well as for steganography applications of hiding secret speech messages for voice mail security. The proposed technique exploits the low-pass spectral properties of speech signals to embed another parametric signal in the low-amplitude high-frequency part of a host speech signal spectral magnitude. Experimental tests on several speech signals show that our technique is capable of hiding narrowband speech CELP-based message inside another host wideband speech segment to produce a stego wideband speech segment that is indistinguishable from the original host speech, while being able to extract the hidden narrowband speech message without any degradations in quality.

Codebook Optimization in Variable-Rate CELP Coders with Sparse Codebooks

Abstract: This $aper reports on efforts to improve the excitation codebook in variable-rate CELP coding of Korean speech. The locay optimized codebook, which still remains sparse and circqar, can produce an average gain of 0.85 dB in SNR.. Inf rmal listening tests confirm the im,provement in speech quiality. 7

Efficient excitation model and fast selection in CELP coding of speech.

Abstract: The paper discusses several new approaches for efficiently modeling and selecting the excitation in CELP coding of speech. Modified error criteria and structured codebooks lead to a wide range of complexity reduction methods, that are evaluated in terms of quality and computational requirements. A very low complexity, though high quality, Regular Pulse (RP) CELP technique is then derived. Finally we address the design of a robust 6 kbps RPCELP coder for mobile radio communications.

Linear prediction techniques in the Walsh spectral domain for speech analysis and synthesis

Abstract: A method for LPC analysis in a transformed domain (LPCTD) has been developed theoretically and studied experimentally in the Walsh-Hadamard domain (LPCWHD) for low-bit- rate coding of speech signals . Speech signals in the Walsh-Hadamard domain have been modelled by their largest variance coefficients and a few prediction coefficients which represent the remaining coefficients. Determination of the prediction coefficients has been based on the correlation between the spectral coefficients. Intelligible speech at bit-rates of 8 kb/s and 4 kb/s was achieved when 16 and 64 point Walsh-Hadamard transforms were used, respectively. At the latter bit-rate the quality was significantly improved when unvoiced sounds were coded seperately by their largest variance coefficients. The main advantage of LPCWHD system is its simplicity which can lead to a far less complex implementation than that of vocoder systems.