TIFs appear less focused than JPG equivalent
Open, NormalPublic

Description

Author: M8R-udfkkf

Description:
It appears that TIFs are slightly less focused (more blurred) than their JPG equivalent.

My bot uploaded these two files:

https://commons.wikimedia.org/wiki/File:071017_NRCS_Sterling_003_-_Ohio_%28717110%29%28NRCS_Photo_Gallery%29.tif

https://commons.wikimedia.org/wiki/File:071017_NRCS_Sterling_003_-_Ohio_%28717110%29%28NRCS_Photo_Gallery%29.jpg

The JPG one was converted from the tif with imagemagick (python):
call(['convert', 'currentfile.tif','-quality', '97', 'currentfile.jpg'])

Although the jpg is 97% of the tif quality, it appears to have better quality.

Am I mistaken or is there a reason for this?


Version: 1.21.x
Severity: normal

bzimport added a subscriber: Unknown Object (MLST).
bzimport set Reference to bz45212.

In the thumbnails of those images?

(In reply to comment #1)

In the thumbnails of those images?

And do you mean the png or the jpg thumbnail of the tiff (we support both. Jpg is the default).

Its possible that different sharpening is applied to tiffs than to jpgs (not sure off the top of my head. I would be surprised though). Its also possible that different scaling algorithms may be used for the different formats or something like that.

mcdevitd wrote:

*** Bug 18014 has been marked as a duplicate of this bug. ***

mcdevitd wrote:

This is also true of .jpg thumbnails of PNG uploads, I assume for the same reason (see duplicate bug report).

(In reply to Dominic from comment #5)

This is also true of .jpg thumbnails of PNG uploads, I assume for the same
reason (see duplicate bug report).

We dont do jpg thumbs of png files (png files get png thumbs), but yes, pngs are not sharpened. Only jpgs get sharpened.

I believe comment 2 is incorrect...

mcdevitd wrote:

(In reply to Bawolff (Brian Wolff) from comment #6)

(In reply to Dominic from comment #5)
> This is also true of .jpg thumbnails of PNG uploads, I assume for the same
> reason (see duplicate bug report).

We dont do jpg thumbs of png files (png files get png thumbs), but yes, pngs
are not sharpened. Only jpgs get sharpened.

Yeah, I misspoke. I should have said JPG versions of PNGs.

The current tiff thumbnails are of such poor quality that Commons users are uploading duplicate jpegs. This is a lot of extra work and puts and extra strain on the Commons community because everything needs to be done twice. Raising the priority of this bug.

I would like to fix this bug at the same time as bug 52045, since we're be changing the rendering config with that bug, so might as well do it all at once.

Jdforrester-WMF moved this task from Untriaged to Backlog on the Multimedia board.Sep 4 2015, 6:39 PM
Restricted Application added subscribers: Steinsplitter, Matanya, Aklapper. · View Herald TranscriptSep 4 2015, 6:39 PM

Add Comment