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

[S. R. Quackenbush]

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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