[Fwd: [Mp4-tech] [Audio] Difference in ISO standard and ISO reference!]

[Dattaguru B.N.]

Dear All,
Thanks for your support and suggestions.  To check my
understanding, 
the updated standard document is 
N6432 (ISO/IEC 14496-3:2001/AMD1:2003/Cor.1:2003(E)).
Dear Mr. KK, are you referring to this document? If I
am wrong, please correct!!
Thanks again,
Regards,
Datta
--- kk codingtechnologies.com wrote:
> Dear Datta,
> 
> The reference software is correct and the text has
> been updated with 
> ISO/IEC 14496-3:2001/AMD1:2003/CORR.1:2004 and is to
> the best of our 
> knowledge correct as well.
> I have implemented the reference software envelope
> adjuster with the exact 
> same loop-structure and data storage as in the
> revised text according to 
> the corrigendum, and I get bit identical results
> with "normal" reference 
> software implementation.
> How to handle data storage is in my mind clearly
> defined for all variables 
> (no variable is defined without stating its
> corresponding range). How you 
> implement the data storage is of course up to you,
> as long as it does not 
> change the definition of the variables, i.e. for
> what time and frequency 
> range they are valid.
> 
> Best regards
> Kristofer
> 
> ---------------------------------------------------
> Kristofer Kjörling
> Senior Research Engineer
> Coding Technologies
> 
> phone : + 46 - (0)8 - 442 91 66
> fax:       + 46 - (0)8 - 33 09 88
> email: kk codingtechnologies.com
> 
> 
> > 
> > ----- Message from "Dattaguru B.N."
> <dattagurubn yahoo.com> on Sun, 
> > 18 Jul 2023 23:08:50 -0700 (PDT) -----
> > 
> > To:
> > 
> > Mp4-tech lists.mpegif.org
> > 
> > Subject:
> > 
> > [Mp4-tech] [Audio] Difference in ISO standard and
> ISO reference!
> > 
> > Dear All,
> > 
> > While analysing the ISO reference
> code(15-Mar-2004)
> > and ISO standard for SBR(N5570 a.k.a ISO/IEC
> > 14496-3:2001/FDAM 1:2003(E)), I found some of the
> > difference listed here under.  These are found to
> be
> > crucial from the perspective of the conformance,
> when
> > we were testing the decoder. 
> > 
> > Can anybody suggest me how to correlate between
> > standard and the reference?  Or is it that I am
> using
> > standard which is not upto date??? If so, how do I
> get
> > the most recent version.
> > 
> > 1. HFAdjustment: while estimating the current
> Envelope
> > (sec.4.6.18.7.3 in N5570), the reference decoder
> will
> > perform the calculation of Ecurr in two different
> > loops with a single loop!   I tried to match these
> two
> > loops, but the loop variables were found to be un
> > related!!!  The standard clearly given different
> loop
> > variables for two conditions.
> > 
> > 2. Storing of Previous data:  The standard does
> not
> > specify anything about the storing of previous
> data. 
> > We tried to follow the standard, and were storing
> it
> > at the end of decoding.  But, the reference
> decoder
> > will store some of the data at the same place
> where
> > new data gets calculated.
> > 
> > These are the few examples. Similar problems also
> can
> > be found in other modules as well.
> > 
> > Thanks in advance,
> > Thanks and regards,
> > Datta
> > 
> > 
> > 
> > 
> > 
> > 
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> 
> 

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