Stephane Ragot

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carles roca-cuberes

Pompeu Fabra University

Luis Garcia Fanlo

Universidad de Buenos Aires

Wilson lopez-lopez

Pontificia Universidad Javeriana

Asrani Hj Lit

Universiti Malaysia Sarawak (UNIMAS)

Kalyan Das

National Institute of Food Technology Entrepreneurship and Management (NIFTEM)

Frederic Guerrero-Solé

Pompeu Fabra University

Rossitza Goleva

New Bulgarian University

Taj Shaik

JNTU,Anantapur

Anil Minhans

Universiti Teknologi Malaysia - UTM

Dr R N Patel

Gujarat Technological University

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Papers by Stephane Ragot

Optimized Low-Bit Rate Parametric Coding/Decoding

Controlling a Noise-Shaping Feedback Loop in a Digital Audio Signal Encoder

Transmission error dissimulation in a digital signal with complexity distribution

Coding of Digital Audio Signals

Hierarchical coding of digital audio signals

Method for Binary Coding of Quantization Indices of a Signal Envelope, Method for Decoding a Signal Envelope and Corresponding Coding and Decoding Modules

Optimized Parametric Stereo Decoding

Coding with noise shaping in a hierarchical coder

Methods and apparatus for coding digital audio signals using a filtered quantizing noise

Processing of Bit Errors in a Digital Audio Bit Frame

Method for switching rate and bandwidth scalable audio decoding rate

Synthesis of Lost Blocks of a Digital Audio Signal, with Pitch Period Correction

Encoding/Decoding of Digital Signals, Especially in Vector Quantization With Permutation Codes

Pre-Echo Attenuation in a Digital Audio Signal

Limitation of distortion introduced by a post-processing step during digital signal decoding

A 8–32 KBIT/S Scalable Wideband Speech and Audio Coding Candidate for ITU-T G729EV Standardization

2006 IEEE International Conference on Acoustics Speed and Signal Processing Proceedings, 2006

ABSTRACT This paper describes a 8-32 kbit/s scalable speech and audio coder submitted as a candid... more ABSTRACT This paper describes a 8-32 kbit/s scalable speech and audio coder submitted as a candidate for the ITU-T G729-based embedded variable bitrate (G729EV) standardization. The coder is built upon a 3-stage coding structure consisting of: narrowband cascade CELP coding at 8 and 12 kbit/s, bandwidth extension based on wideband linear-predictive coding (WB-LPC) at 14 kbit/s, and MDCT coding in a WB-LPC weighted signal domain from 14 to 32 kbit/s. ITU-T test results showed that this coder passed all the requirements of the G729EV qualification phase

Wideband LSF quantization by generalized voronoi codes

Presented a method for quantizing the wideband line spectrum frequencies (LSF) with a specific cl... more Presented a method for quantizing the wideband line spectrum frequencies (LSF) with a specific class of near-ellipsoidal lat- tice codes referred to as "generalized Voronoi codes". Opti- mization procedures are described with respect to a weighted mean-square error (WMSE). The lattices , or are applied to quantize the LSF with no frequency splitting. Re- sults indicate that near-ellipsoidal lattice quantization allows to develop efficient one-stage algebraic wideband LSF quantiza- tion at competitive bit rates.

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Design of test sequences for G.729 Annex E

The 11.8 kb/s extension of the G.729 codec, also known as Annex E of the G.729 Recommendation, ha... more The 11.8 kb/s extension of the G.729 codec, also known as Annex E of the G.729 Recommendation, has been ratified by the ITU-T. This paper describes how the related test sequences have been designed, using the fixed-point C simulation of the codec. The design method is based on the concept of coverage, already used in the design of test sequences for the G.729 codec. Coverage ensures that all possible parameter values are observed in the bitstream, and all portions of the algorithm are executed at least once. Experiments showed that this approach guarantees a satisfying reliability

IEEE 2010 Multimedia Signal Processing Conf

by Stephane Ragot and Pascal Scalart

In this paper, we present a novel, frequency-domain stereo to mono downmixing, which preserves th... more In this paper, we present a novel, frequency-domain stereo to mono downmixing, which preserves the energy of spectral components and avoids setting the left or right channel as a phase reference. Based on this downmixing technique, a parametric stereo analysis-synthesis model is described in which subband stereo parameters consist of interchannel level differences and phase differences between the mono signal and one of the stereo channels (left or right). This model is applied to the stereo extension of ITU-T G.722 at 56+8 and 64+16 kbit/s with a frame length of 5 ms. AB test results are provided to assess the quality of the proposed downmixing technique. In addition, the quality of the proposed G.722-based stereo coder is compared against reference coders (G.722.1 at 24 and 32 kbit/s dual mono and G.722 at 64 kbit/s dual mono) for clean speech, noisy speech and music.

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Transform Audio Coding with Arithmetic-Coded Scalar Quantization and Model-Based Bit Allocation

2007 IEEE International Conference on Acoustics, Speech and Signal Processing - ICASSP '07, 2007

In this paper we present a new model-based method to code the transform coef cients of audio sign... more In this paper we present a new model-based method to code the transform coef cients of audio signals. The histogram of transform coef cients is approximated by a generalized Gaussian model for ef cient model-based bit allocation and the spectrum is coded by scalar quantization followed by arithmetic coding. An example coder operating at 16 kHz and using predictive modi ed discrete cosine transform (MDCT) coding is described. We compare the performance of the proposed coder with ITU-T G.722.1. Objective and subjective quality results are presented. The proposed coder is better than ITU-T G.722.1 at 24 kbit/s and equivalent at 32 kbit/s.

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Optimized Low-Bit Rate Parametric Coding/Decoding

Controlling a Noise-Shaping Feedback Loop in a Digital Audio Signal Encoder

Transmission error dissimulation in a digital signal with complexity distribution

Coding of Digital Audio Signals

Hierarchical coding of digital audio signals

Method for Binary Coding of Quantization Indices of a Signal Envelope, Method for Decoding a Signal Envelope and Corresponding Coding and Decoding Modules

Optimized Parametric Stereo Decoding

Coding with noise shaping in a hierarchical coder

Methods and apparatus for coding digital audio signals using a filtered quantizing noise

Processing of Bit Errors in a Digital Audio Bit Frame

Method for switching rate and bandwidth scalable audio decoding rate

Synthesis of Lost Blocks of a Digital Audio Signal, with Pitch Period Correction

Encoding/Decoding of Digital Signals, Especially in Vector Quantization With Permutation Codes

Pre-Echo Attenuation in a Digital Audio Signal

Limitation of distortion introduced by a post-processing step during digital signal decoding

A 8–32 KBIT/S Scalable Wideband Speech and Audio Coding Candidate for ITU-T G729EV Standardization

2006 IEEE International Conference on Acoustics Speed and Signal Processing Proceedings, 2006

Wideband LSF quantization by generalized voronoi codes

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Design of test sequences for G.729 Annex E

IEEE 2010 Multimedia Signal Processing Conf

by Stephane Ragot and Pascal Scalart

Download

Transform Audio Coding with Arithmetic-Coded Scalar Quantization and Model-Based Bit Allocation

2007 IEEE International Conference on Acoustics, Speech and Signal Processing - ICASSP '07, 2007

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