Lossless audio coding with MPEG-4 structured audio

2003 ◽  
Author(s):  
N. Vasiloglou ◽  
R.W. Schafer ◽  
M.C. Hans
Keyword(s):  
Audio Coding ◽  
Structured Audio

Audio coding using variable-depth multistage quantization

1998 ◽  
Vol 6 (2) ◽  
pp. 186-189 ◽  
Author(s):  
F. Kossentini ◽  
M. Macon ◽  
M.J.T. Smith
Keyword(s):  
Audio Coding ◽  
Variable Depth

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.

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