[Mp4-tech] [HE-AAC]understanding of AAC+ conformance test

[Andy Quan]

I am recently working on AAC+ ISO conformance test(SBR, 14496-4) for a
fixed point decoder. One thing that keeps puzzling me is what the
significance of passing conformance test is.
As the whole suite of conformance test compasses many different test
streams with different accuracy criteria of both MaxDiff and RMS
threshold, failure in any of them leads to being "not passed" in this
"conformance test". However some of these test cases are not meant for
syntax checking but for computational accuracy. As we all know, fixed
point decoder prioritizes performance and usually puts computational
accuracy a little behind.
In such cases, i mean if it can not pass all CT tests, can we still
OFFICIALLY call it "ISO compliant decoder"? (I would rather take
"compliant" as "compliant syntax parsing") I find a lot of commercial
and embedded dedicated AAC+ codecs claim themselves "fully compliant
to ISO". Does this mean that they can pass this ISO conformance test
suite?
Any one got comment? Thanks in advance.
-- 
Regards,
Andy Quan