#423 WEBP color saturation degradation

[Przemysław Sobala]

Hi
I'm using GraphicsMagick 1.3.25 and libwebp 0.5.2 and I've noticed a color change (saturation degradation) when converting images from JPG to WEBP, eg.:

gm convert http://d.wpimg.pl/1972545173--1156527689/paulina-sykut.jpg ir.webp

Please compare skin color in source jpg and target webp (http://pasteboard.co/50Q0V8llI.png).

I filed an issue on webp project: https://bugs.chromium.org/p/webp/issues/detail?id=346
and, as it turnes out, preserving metadata from original resolves this problem.

As gm identify -verbose shows webp files don't have ICC profile preserved and that's why above image has decreased color saturation. Could you implement copy'ing metadata as cwebp <input> -metadata {all,icc,exif,..} -o <output>?

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Best Regards
Przemysław Sobala

[Bob Friesenhahn]

Mercurial changeset 15258:567f87e1410d adds EXIF and ICC metadata support starting with libwebp 0.5.0.