scholarly journals Dithered Quantization for Frequency-Domain Speech and Audio Coding

2018 ◽  
Author(s):  
Tom Bäckström ◽  
Johannes Fischer ◽  
Sneha Das
Keyword(s):  
Frequency Domain ◽  
Audio Coding ◽  
Dithered Quantization ◽  
Speech And Audio Coding

scholarly journals Progress in LPC-based frequency-domain audio coding

2016 ◽  
Vol 5 ◽  
Author(s):  
Takehiro Moriya ◽  
Ryosuke Sugiura ◽  
Yutaka Kamamoto ◽  
Hirokazu Kameoka ◽  
Noboru Harada
Keyword(s):  
Frequency Domain ◽  
Linear Prediction ◽  
Frequency Resolution ◽  
Audio Coding ◽  
Coding Efficiency ◽  
Coding Schemes ◽  
Coding Standards ◽  
Linear Prediction Coding ◽  
Speech And Audio Coding ◽  
Model Frequency

This paper describes the progress in frequency-domain linear prediction coding (LPC)-based audio coding schemes. Although LPC was originally used only for time-domain speech coders, it has been applied to frequency-domain coders since the late 1980s. With the progress in associated technologies, the frequency-domain LPC-based audio coding scheme has become more promising, and it has been used in speech/audio coding standards, such as MPEG-D unified speech and audio coding and 3GPP enhanced voice services since 2010. Three of the latest investigations on the representations of LPC envelopes in frequency-domain coders are shown. These are the harmonic model, frequency-resolution warping and the Powered All-Pole Spectral Envelope, all of which are aiming at further enhancement of the coding efficiency.

scholarly journals Superwideband Bandwidth Extension Using Normalized MDCT Coefficients for Scalable Speech and Audio Coding

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Young Han Lee ◽  
Seung Ho Choi
Keyword(s):  
Discrete Cosine Transform ◽  
Audio Coding ◽  
Bandwidth Extension ◽  
Spectral Parameters ◽  
Cosine Transform ◽  
Modified Discrete Cosine Transform ◽  
Audio Codec ◽  
Speech And Audio Coding

A bandwidth extension (BWE) algorithm from wideband to superwideband (SWB) is proposed for a scalable speech/audio codec that uses modified discrete cosine transform (MDCT) coefficients as spectral parameters. The superwideband is first split into several subbands that are represented as gain parameters and normalized MDCT coefficients in the proposed BWE algorithm. We then estimate normalized MDCT coefficients of the wideband to be fetched for the superwideband and quantize the fetch indices. After that, we quantize gain parameters by using relative ratios between adjacent subbands. The proposed BWE algorithm is embedded into a standard superwideband codec, the SWB extension of G.729.1 Annex E, and its bitrate and quality are compared with those of the BWE algorithm already employed in the standard superwideband codec. It is shown from the comparison that the proposed BWE algorithm relatively reduces the bitrate by around 19% with better quality, compared to the BWE algorithm in the SWB extension of G.729.1 Annex E.

scholarly journals Single-Mode-Based Unified Speech and Audio Coding by Extending the Linear Prediction Domain Coding Mode

ETRI Journal ◽  
2017 ◽  
Vol 39 (3) ◽  
pp. 310-318 ◽  
Author(s):  
Seungkwon Beack ◽  
Jongmo Seong ◽  
Misuk Lee ◽  
Taejin Lee
Keyword(s):  
Linear Prediction ◽  
Single Mode ◽  
Audio Coding ◽  
Coding Mode ◽  
Speech And Audio Coding

scholarly journals Wide-Band Audio Coding Based on Frequency-Domain Linear Prediction

2010 ◽  
Vol 2010 ◽  
pp. 1-14
Author(s):  
Petr Motlicek ◽  
Sriram Ganapathy ◽  
Hynek Hermansky ◽  
Harinath Garudadri
Keyword(s):  
Frequency Domain ◽  
Linear Prediction ◽  
Wide Band ◽  
Audio Coding
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