[FFmpeg-devel] [Issue 664] [PATCH] Fix AAC PNS Scaling

Robert Swain robert.swain
Tue Oct 7 22:17:04 CEST 2008


2008/10/7 M?ns Rullg?rd <mans at mansr.com>:
> "Robert Swain" <robert.swain at gmail.com> writes:
>> 2008/10/7 Alex Converse <alex.converse at gmail.com>:
>>> On Tue, Oct 7, 2008 at 3:24 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
>>>> iam not sure how you can call that "far more significance" on one hand and
>>>> pretend that skiping per band normalization would be ok OTOH.
>>>
>>> Says the man who made Rob change it from the correct per band
>>> implementation in the first place because he didn't know what he was
>>> talking about, who likes to argue the finer points of the AAC
>>> specification without even having access to a copy of the conformance
>>> rules.
>>>
>>> Per band is what MPEG asks for. Not doing it per band results in
>>> statistics that deviate significantly from the sample statics measured
>>> by the encoder that the decoder is trying to mimic. They have made
>>> this clear on numerous occasions.
>>
>> Hmm, a slightly aggressive tone...
>>
>> Personally, I think we should re-implement the per-band normalisation
>> to be conforming. Any complaints about doing this?
>
> There is never an excuse for not conforming to specs, no matter how
> stupid the specs are.

Well, we don't conform with regard to window transitions. Some
transitions are suggested to be meaningless in the specification but
not invalid. We conduct windowing differently in these cases.

Rob



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