Last modified: 2014-03-26 18:12:31 UTC

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Bug 51449 - Improve JPG sharpening algorithm
Improve JPG sharpening algorithm
Status: NEW
Product: MediaWiki extensions
Classification: Unclassified
VipsScaler (Other open bugs)
unspecified
All All
: Normal enhancement (vote)
: ---
Assigned To: Nobody - You can work on this!
:
Depends on:
Blocks: 51451
  Show dependency treegraph
 
Reported: 2013-07-16 17:13 UTC by Greg Grossmeier
Modified: 2014-03-26 18:12 UTC (History)
7 users (show)

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Attachments

Description Greg Grossmeier 2013-07-16 17:13:33 UTC
From bug 51370c2 (Eduard):
> One question regarding JPGs:
> You apply sharpening depending on how much they are shrunk. Have you tried to
> use a continuous function for the amount of sharpening instead of discrete
> values at fixed steps (as also indicated in the source code comment above)?
> 
> Without having done any tests I could imagine this would yield more consistent
> quality for all sizes.
Comment 1 Nemo 2014-03-26 18:12:31 UTC
Are there default options that we can rely upon instead of guessing best settings on our own? It seems 7.36.0 added something that may of use, optimize_coding option; and 7.38 some more. http://libvips.blogspot.it/2013/11/tips-and-tricks-for-vipsthumbnail.html has some info

«$ vipsthumbnail 42-32157534.jpg -o x.jpg[optimize_coding,strip]
$ ls -l x.jpg
-rw-r--r-- 1 john john 3600 Nov 12 21:27 x.jpg
Tiny! About half the size of where we started with no quality loss.»

(Compared to itself, not to imagemagick.)

Note that thumb weight is now a concern, especially on mobile which is an increasing portion of Wikimedia traffic: https://www.mediawiki.org/wiki/Talk:Requests_for_comment/Reducing_image_quality_for_mobile#Fundamentals

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