From: David Kastrup <dak@gnu.org>
To: emacs-devel@gnu.org
Subject: Re: Image rescaling
Date: Mon, 15 Sep 2014 17:13:53 +0200 [thread overview]
Message-ID: <87egvcrk5q.fsf@fencepost.gnu.org> (raw)
In-Reply-To: jwvppex6jvj.fsf-monnier+emacs@gnu.org
Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> Rescaling is apparently a pretty tricky thing that is mostly implemented
>> wrong:
>
>> http://www.4p8.com/eric.brasseur/gamma.html
>
> Rescaling an image is exactly the same problem as resampling an audio
> file (e.g. to play it at 48KHz instead of the 44.1KHz used on the CD
> from which it came).
>
> Doing it naively works, but in some cases gives very poor
> results, indeed.
Nice meditation but not related to the referenced article. The article
is concerned about non-linear quantization. That's "exactly the same
problem" as using a good 48kHz to 44.1kHz resampling algorithm on
uLaw-quantized audio data rather than linearly-quantized data.
Entirely different problem to mess up on.
--
David Kastrup
next prev parent reply other threads:[~2014-09-15 15:13 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-15 12:45 Image rescaling Lars Magne Ingebrigtsen
2014-09-15 12:55 ` joakim
2014-09-15 13:03 ` Lars Magne Ingebrigtsen
2014-09-15 14:27 ` Stefan Monnier
2014-09-15 15:13 ` David Kastrup [this message]
[not found] ` <COL131-W90F448E3DC24C8E66A0E4D84C90@phx.gbl>
[not found] ` <m3d2as98w1.fsf@stories.gnus.org>
2014-09-18 17:03 ` Mirek Kaim
2014-09-15 15:12 ` joakim
2014-09-15 16:14 ` Lars Magne Ingebrigtsen
2014-09-15 19:01 ` joakim
2014-09-15 19:59 ` Lars Magne Ingebrigtsen
2014-09-15 20:00 ` joakim
2014-09-16 0:07 ` Stefan Monnier
2014-09-16 9:42 ` Lars Magne Ingebrigtsen
2014-09-16 11:22 ` Dmitry Antipov
2014-09-16 11:37 ` Lars Magne Ingebrigtsen
2014-09-16 14:42 ` Eli Zaretskii
2014-09-16 14:52 ` Lars Magne Ingebrigtsen
2014-09-16 3:10 ` Stephen J. Turnbull
2014-09-16 14:33 ` Eli Zaretskii
2014-09-19 16:48 ` Ivan Kanis
2014-09-30 14:19 ` Lars Magne Ingebrigtsen
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