Issue 311 in webp: CMYK - Unsupported Color Conversion Format

[khanduja… via monorail]

Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 311 by khanduja...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311

What steps will reproduce the problem?
1. Run `cwebp -jpeg_like -af input.jpeg(withCMYKprofile) -o output.jpeg`

What is the expected output? What do you see instead?

Well, I dont want to see "Unsupported color conversion request", so my question is there a plan for supporting this. Or possibly am I doing something wrong?

What version of the product are you using? On what operating system?

cwebp - 0.5.1
OS - ubuntu 14.04

Thank you.



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[khanduja… via monorail]

Comment #1 on issue 311 by khanduja...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c1

A sample file:

Attachments:
CMYK.jpeg 2.9 MB

[pascal.m… via monorail]

Updates:
Status: Invalid

Comment #2 on issue 311 by pascal.m...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c2

Unfortunately, the error message emanate from the JPEG decoding library that is installed on your system (or used during the compilation of cwebp).

There's no much libwebp can do here. If it's a system-wide library problem, other conversion tools must be failing too, on your machine.

[khanduja… via monorail]

Comment #3 on issue 311 by khanduja...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c3

I am using imagemagick and it is able to convert from CMYK to RGB images. A lot of operation done in my service(multiple resize imagemagick command) is able to process CMYK images. However, cwebp command only fails.

Also, "convert -colorspace RGB CMYK.jpeg RGB.jpeg" works with final output as sRGB.

Maybe the libjpeg used by cwebp and imagemagick are different, but I am not sure how I can find that for cwebp.

Also, cwebp was installed after imagemagick.

[khanduja… via monorail]

Comment #4 on issue 311 by khanduja...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c4

I am talking about this: https://groups.google.com/a/webmproject.org/forum/#!topic/webp-discuss/MH8q_d6M1vM

This post is from over 5 years ago. Also, libjpeg should be supporting this, if not CMYK would have even adopted by systems universally, I think(?).

[jz… via monorail]

Comment #5 on issue 311 by jz...@google.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c5

It's possible ImageMagick is doing the conversion on its own. djpeg -rgb will fail with this image as well. There's some related discussion in debian [1] and libjpeg-turbo [2] bugs.

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=718604
[2] https://sourceforge.net/p/libjpeg-turbo/patches/15/

[khanduja… via monorail]

Comment #6 on issue 311 by khanduja...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c6

That's some really good references. Please give me sometime to go through it. And yeah, djpeg didnt support it natively. I have opened a discussion to see how this is being done on the end of imagemagick. Hope to find some information on how this can be tackled.

https://imagemagick.org/discourse-server/viewtopic.php?f=1&t=30533

Thank you, jzern.

[khanduja… via monorail]

Comment #7 on issue 311 by khanduja...@gmail.com: CMYK - Unsupported Color Conversion Format
https://bugs.chromium.org/p/webp/issues/detail?id=311#c7

Thank you. Tracked in Imagemagick github library: https://github.com/ImageMagick/ImageMagick/blob/2c02f097b503b29aad7db4c2456ddd0d5ddee8d7/coders/jpeg.c#L1435 . This is done internally by imagemagick.

Apologies for any inconvenience caused.

[MND LSN]

I am on `Ubuntu 20.04 (LTS) x64` with `cwebp -version 1.2.4` while processing about 320,000 files with this 

```

nohup `for file in img/*; do cwebp -quiet -q 50 "$file" -o "${file%.*}.webp"; done`

```

I get this error 

```

libjpeg error: Unsupported color conversion request
Error! Could not process file img/037946023.jpg
Error! Cannot read input picture file 'img/037946023.jpg'

```

Attached below the file 'img/037946023.jpg that yeah is CMYK 

```

identify -format "%[colorspace]" ~/037946023.jpg
CMYK%   

```

Why still this unsupported?  

[M L]

```

➜  ~ cwebp -q 50 037946023.jpg -o 037946023.webp

libjpeg error: Unsupported color conversion request

Error! Could not process file 037946023.jpg
Error! Cannot read input picture file '037946023.jpg'

➜  ~

➜  ~ magick 037946023.jpg -quality 50 -define webp:lossless=false 037946023.webp
➜  ~ file 037946023.webp
037946023.webp: RIFF (little-endian) data, Web/P image, VP8 encoding, 550x550, Scaling: [none]x[none], YUV color, decoders should clamp

➜  ~

```