[Mp4-tech][audio] High sampling rates in AAC - why?

[S. R. Quackenbush]

Re: wider bandwidth
Theoretically correct, but in practice most systems will bandlimit output at
20 kHz.
Schuyler
---
Dr. Schuyler Quackenbush, Audio Research Labs
336 Park Ave, Suite 200,  Scotch Plains, NJ 07076
office: 908 490 0700	  srq audioresearchlabs.com
mobile: 908 612 9423
fax:    908 842 9151	  www.audioresearchlabs.com
> -----Original Message-----
> From: Dattaguru B.N. [mailto:dattagurubn yahoo.com]
> Sent: Wednesday, October 27, 2023 2:55 AM
> To: srq ieee.org; D.Domazet; mp4-tech lists.mpegif.org
> Subject: RE: [Mp4-tech][audio] High sampling rates in AAC - why?
>
>
> Hi,
>
> I feel, high sampling rates would help us in better
> band widths.  Higher the sampling rate, better will be
> the band width.
> If I am wrong, please correct.
>
> Thanks
> Datta
>
> --- "S. R. Quackenbush" <srq ieee.org> wrote:
>
> > Hi,
> >
> > One very good reason for running AAC at 96 kHz is
> > that it interoperates with
> > 96 kHz D/A converter, and these converters permit an
> > analog anti-imaging
> > filter with much lower slope (e.g. passband at 20
> > kHz, stopband at 48 kHz)
> > and hence less phase distortion in the conversion.
> >
> > Schuyler Quackenbush
> > ---
> > Dr. Schuyler Quackenbush, Audio Research Labs
> > 336 Park Ave, Suite 200,  Scotch Plains, NJ 07076
> > office: 908 490 0700	  srq audioresearchlabs.com
> > mobile: 908 612 9423
> > fax:    908 842 9151	  www.audioresearchlabs.com
> >
> >
> >
> > > -----Original Message-----
> > > From: mp4-tech-bounces lists.mpegif.org
> > > [mailto:mp4-tech-bounces lists.mpegif.org]On
> > Behalf Of D.Domazet
> > > Sent: Tuesday, October 26, 2023 6:12 AM
> > > To: mp4-tech lists.mpegif.org
> > > Subject: [Mp4-tech][audio] High sampling rates in
> > AAC - why?
> > >
> > >
> > > Hi all,
> > > As we know, AAC supports high sampling rates, for
> > example 88.2kHz
> > > and 96kHz.
> > > What is the purpose of this? If I was to test the
> > encoder for quality at
> > > this sampling rates, how would I do that? Is
> > down-sampling a must since
> > > humans can't hear this high freqs? Or AAC is used
> > by bats and whales...
> > >
> > > Daniel
> > >
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>
>
>
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