Bug 480651 - Exporting to JXL lowers the colour depth to 8 bpp
Summary: Exporting to JXL lowers the colour depth to 8 bpp
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Plugin-DImg-QImage (show other bugs)
Version: 8.2.0
Platform: openSUSE Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-02-01 03:01 UTC by Rafael Linux User
Modified: 2024-02-01 22:31 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In: 8.3.0


Attachments
AppImage freezed after click right mouse button on thumbnail (231.61 KB, image/webp)
2024-02-01 22:20 UTC, Rafael Linux User
Details

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Description Rafael Linux User 2024-02-01 03:01:32 UTC
SUMMARY
When exporting 16bpp TIFF files to JXL, Digikam lowers the colour depth to 8bpp. Please fix the problem, as I always use Digikam and I want to convert all my TIFF files to JXL.

I would also like to comment that the JXL format has more advanced export options that are not available in Digikam.

STEPS TO REPRODUCE
1. Select a TIFF file with 16 bpp color
2. Click on "Batch process"
3. Select "Convert to JXL" and "Lossless file"
4. Click on "Execute" ("Play" button)

OBSERVED RESULT
Exported JXL file bit depth is lowered to 8 bpp

EXPECTED RESULT
Exporte JXL file should have same bit depth than original TIFF file.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20240128
KDE Plasma Version: 5.27.10
KDE Frameworks Version: 5.114.0
Qt Version: 5.15.12
Kernel Version: 6.7.1-2-default (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
GIMP and Krita export same TIFF file to JXL respecting bit depth.
Comment 1 caulier.gilles 2024-02-01 06:40:17 UTC
The JXL plugin loader use QImage container through the KImageFormat framework from KDE:

Sound like the current code is able to handle > 8 bits colors depth:
 
https://invent.kde.org/frameworks/kimageformats/-/blob/master/src/imageformats/jxl.cpp?ref_type=heads#L248
https://invent.kde.org/frameworks/kimageformats/-/blob/master/src/imageformats/jxl.cpp?ref_type=heads#L482

Gilles Caulier
Comment 2 caulier.gilles 2024-02-01 06:41:33 UTC
As you use KDE framework 5.114.0, it's the current code used supporting 16 bits color depth.

Gilles Caulier
Comment 3 Maik Qualmann 2024-02-01 06:53:33 UTC
This problem is fixed in digiKam-8.3.0 with Bug 479497 and support for RGBA64 QImage from 16bit DImg. The prerequisite is that the KImageFormats support this. A test here with a CR3 to JXL conversion results in a 16 bit JXL image.

Maik
Comment 4 caulier.gilles 2024-02-01 07:06:39 UTC
Rafael,

If you want to test, try the current 8.3.0 pre-release AppImage bundle for Linux here :

https://files.kde.org/digikam/

Gilles Caulier
Comment 5 Rafael Linux User 2024-02-01 08:12:35 UTC
(In reply to caulier.gilles from comment #4)
> Rafael,
> 
> If you want to test, try the current 8.3.0 pre-release AppImage bundle for
> Linux here :
> 
> https://files.kde.org/digikam/
> 
> Gilles Caulier

Thank you Gilles, I'll try tonight.
Comment 6 Rafael Linux User 2024-02-01 22:19:37 UTC
It works, as you told. However, in this version - I don't know why, cause I use usually AppImages withuot issues - when I click right mouse button on a thumbnail to show contextual menu, AppImage seems like freezed (even is greyed by Plasma) and doesn't react to any user action (can resize window, but no interaction at all).

In attached screenshot you can see the auto-showed metadata window that appear when mouse is over a thumbnail, but it's freezed cause I click with right mouse button over
Comment 7 Rafael Linux User 2024-02-01 22:20:17 UTC
Created attachment 165456 [details]
AppImage freezed after click right mouse button on thumbnail
Comment 8 Maik Qualmann 2024-02-01 22:25:13 UTC
The problem with the AppImage in up to date Linux distributions is already known, see this Bug 480134

Maik
Comment 9 Rafael Linux User 2024-02-01 22:31:03 UTC
(In reply to Maik Qualmann from comment #8)
> The problem with the AppImage in up to date Linux distributions is already
> known, see this Bug 480134
> 
> Maik

That's perfect. I thought I should let you know, but I see it wasn't necessary because you already knew.

Thanks for adding the 16bit functionality so quickly.