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Re: perceptual audio codecs

I have to ask: Is this OFFICIAL source code the best known encoder?

You can also get reference models for later MPEG systems, but the question remains there, as well.

On Sat, Apr 12, 2014 at 12:09 AM, Joachim Thiemann <joachim.thiemann@xxxxxxxxx> wrote:
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

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...


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
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Joachim Thiemann :: http://jthiem.bitbucket.org ::

James D. (jj) Johnston
Independent Audio and Electroacoustics Consultant