Re: perceptual audio codecs (Joachim Thiemann )


Subject: Re: perceptual audio codecs
From:    Joachim Thiemann  <joachim.thiemann@xxxxxxxx>
Date:    Sat, 12 Apr 2014 09:09:54 +0200
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

Hello again Alberto, I just want to point out that you can get _official_ source code for two low-bitrate audio codecs: AMR-WB+ and EnAAC+, from the 3GPP standards body. They are very descriptively titled TS26.304 and TS26.410 (for AMR-WB+ and Enhanced aacPlus respectively), and can be downloaded from http://www.3gpp.org/DynaReport/26-series.htm. There are fixed-point versions as well, but the float versions are far more understandable. Enhanced aacPlus - if my memory still somewhat right from 10 years ago - is basically AAC tuned for low bitrate, with bandwidth extension and parametric stereo. AMR-WB+ is a dual-mode LP-based codec, switching between CELP and a transform to code the residual, also with bandwidth extension and parametric stereo. If you look around on the 3GPP website you can also find the source for the ancestors of AMR-WB+ (named, well, AMR and AMR-WB). Since they are designed as purely speech codecs, they are probably not of much interest to you, though I heard that someone did write a MATLAB implementation of one of those at some point. I may be wrong, and I heard about that after I left UdeS anyways... Cheers, Joachim On 9 April 2014 11:57, JesterN Alberto Novello <jestern77@xxxxxxxx> wrote: > Dear List, > I'm reviewing the state of the art of Perceptual Audio Codecs. For this > reason I tried collecting some available MATLAB codecs for testing quality > (in perceptual experiments), compression ratio and speed. I realised there > is not so much code available out there and mostly quite old (probably for > commercial copyright reasons). So I thought of asking here if any of you has > some links to suggest about some available code (C, C++ also possible) > possibly less than a decade old. > Thanks a lot > Alberto > > || | | ||| | || || | ||||| || | || | ||| | ||||| | | ||| | |||| | || |||| > > ALBERTO NOVELLO / JesterN > site: jestern.com > shop: jestern.bandcamp.com > audio: soundcloud.com/jestern > video: vimeo.com/jestern > > || | | ||| | || || | ||||| || | || | ||| | ||||| | | ||| | |||| | || |||| > > If for any reason you wish not to receive any more messages from this email, > please send an email with REMOVE as subject. I'm sorry for the > inconvenience. > Se per qualsiasi ragione non desideri ricevere piu' messaggi da questo > indirizzo, mandami un messaggio con REMOVE nel soggetto. Mi scuso per il > disturbo. -- Joachim Thiemann :: http://jthiem.bitbucket.org :: http://signalsprocessed.blogspot.com


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