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VZpolodov (Valery Zapolodov)
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User Details

User Since
May 4 2021, 1:58 AM (54 w, 4 d)
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Valery Zapolodov [ Global Accounts ]

Recent Activity

Nov 5 2021

VZpolodov added a comment to T26768: PNG thumbnails of SVG images should use sRGB chunk.

Any updates? ImageMagick agreed this is a bug.

Nov 5 2021, 2:50 AM · Thumbor, TestMe, Upstream, Wikimedia-SVG-rendering

Sep 27 2021

VZpolodov added a comment to T270855: Add support for JPEG XL: allow JXL uploads in MediaWiki.

Just FYI: 14 days ago ImageMagick already fixed JXL integration since in 0.5 version JXL now requires setting color space info. JXL can preserve JPEGs losslessly! https://github.com/ImageMagick/ImageMagick/pull/4064

Sep 27 2021, 4:17 PM · Upstream, Commons, Thumbor

May 5 2021

VZpolodov added a comment to T26768: PNG thumbnails of SVG images should use sRGB chunk.

off-topic for this ticket

May 5 2021, 11:00 AM · Thumbor, TestMe, Upstream, Wikimedia-SVG-rendering
VZpolodov added a comment to T26768: PNG thumbnails of SVG images should use sRGB chunk.

Why you are not just using SVG directly??

May 5 2021, 10:10 AM · Thumbor, TestMe, Upstream, Wikimedia-SVG-rendering

May 4 2021

VZpolodov added a comment to T270855: Add support for JPEG XL: allow JXL uploads in MediaWiki.

all the extra color information that current cameras capture.

May 4 2021, 3:11 AM · Upstream, Commons, Thumbor
VZpolodov added a comment to T211667: Study the compression performance of single-frame AV1.

JPEG XL supports mathematically lossless from JPEG convertion and back and also better than AVIF. Soon to be added in Chrome.

May 4 2021, 3:08 AM · Performance-Team
VZpolodov added a comment to T19505: No High Dynamic Range Image (HDRI) file formats allowed on Commons.

AVIF now activly supports HDR with PQ or HLG transfer.

May 4 2021, 2:54 AM · MediaWiki-File-management, Multimedia, Commons
VZpolodov added a comment to T243369: Feature request: Lossless image optimization upon upload.

automatically converts CMYK images to RGB

May 4 2021, 2:52 AM · MediaWiki-extension-requests, MediaWiki-Uploading
VZpolodov added a comment to T272364: Overly blurry JPG thumbnail for certain JPG and TIFF images due to chroma-subsampling not working in CMYK.

This file uses APP14 marker's ColorTranform set to 0, which means RGB for 3 components and CMYK for 4 components. That is a common problem. This file has ColorTranform 2 which is YCCK. See thumbnail, that is broken. https://en.wikipedia.org/wiki/File:Channel_digital_image_CMYK_color.jpg

May 4 2021, 2:44 AM · Upstream, Thumbor
VZpolodov added a comment to T108517: PNG thumbnails issues (tracking).

This uses YCCK color space (K is from CMYK, YCC --> to CMY). Please fix the thumbnail.

May 4 2021, 2:29 AM · Commons, Tracking-Neverending, Multimedia, MediaWiki-File-management
VZpolodov reopened T26768: PNG thumbnails of SVG images should use sRGB chunk as "Open".

gAMA of 0.45454544 is not sRGB, not at all, the sRGB tranfer function is piecewise. It destroyes the picture in mastercard article (see my comment there on talk page) and in SMPTE color bars (in both cases it should be the same 8 bit values, check with Chrome, Photoshop still does not support gAMA, sigh).

May 4 2021, 2:20 AM · Thumbor, TestMe, Upstream, Wikimedia-SVG-rendering