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

[Dattaguru B.N.]

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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