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.

Image predictive coding apparatus, an image prediction decoding device, image prediction encoding method, image prediction decoding method, image prediction encoding program, and image prediction decoding program

Abstract: PROBLEM TO BE SOLVED: To provide a technology capable of realizing efficient coding processing or decoding processing by decreasing the amount of mode information associated with a prediction method for generating an in-image prediction signal in a pixel region. SOLUTION: The image prediction coding apparatus 10 includes: an in-image prediction signal generating method determining section 15 that determines a prediction method derived on the basis of data corresponding to an adjacent region adjacent to an object region and comprising pixel signals having already been reproduced as an R mode prediction method or an L mode prediction method; an in-image prediction signal generating section 16 for generating an in-image prediction signal on the basis of the determined R mode prediction method; a subtractor 18, a conversion section 19, a quantization section 20, and an entropy coding section 25 for coding a residual signal between the pixel signal of the object region and the generated in-image prediction signal. COPYRIGHT: (C)2007,JPO&INPIT

Speech Coding Based on Compressed Sensing and Sparse Representation

Abstract: In this paper, we propose a novel speech coding scheme based on compressed sensing and sparse representation. Compressed sensing (CS) attracts great interest for its ability to utilize a few measurements to recover original signals. Measurements preserve part of speech features while projected by row echelon matrix. A dictionary is learned in order to contain redundant information about speech measurements. The synthesized speech is recovered from a sparse approximation of the corresponding measurement. A rear low-pass filter is adopted to improve the subject quality of synthesized speech. Results show that the proposed coding scheme has achieved average Mean Opinion Score (MOS) of the synthesized speech 3.083 in an appropriate bit rate (4.2 Kbps), which outperforms the quality of Code excited linear prediction (CELP).

A real-time wideband CELP coder for a videophone application

Abstract: In this paper we present an algorithm for the coding of wideband (7 kHz) speech signals at 16 kbps using code excited linear prediction (CELP), primarily intended for use in audio-visual coding systems (e.g., videotelephony) in the ISDN network, or other telecommunication equipment using loudspeaker sound. The algorithm is a full-band approach and much effort has been put into reducing the computational complexity. This has led to a real-time implementation of the present algorithm on a single TMS320C31 DSP (encoder+decoder). Through a formal subjective evaluation we have demonstrated a performance comparable to the CCITT Rec. G.722 subband coder at 64 kbps. >

Study of voice packet reconstruction methods applied to CELP speech coding

Abstract: Four voice packet reconstruction methods used for speech coded by code excited linear prediction (CELP)-type speech coders are described. In the first method, the authors generalize the waveform substitution technique originally developed for the PCM coded speech to the CELP speech coding. In the second method, a priority level is assigned to each speech frame to protect against those perceptually important and hard-to-reconstruct speech frames being lost. The third and fourth methods both split the information bits in a frame into two groups of different levels of importance. In method three, the bits for representing the filter parameters are given high priority and bits for representing the excitation signals are given low priority. Method four is an embedded coding technique based on two-stage CELP. The four methods were tested in combination with a simulated voice activity and queuing model and their performance is discussed. >