Bug 128669 - Use embedded thumbnail for viewing RAW files
Summary: Use embedded thumbnail for viewing RAW files
Alias: None
Product: digikam
Classification: Unclassified
Component: Plugin-RawImport-Native (show other bugs)
Version: unspecified
Platform: Ubuntu Packages Linux
: NOR wishlist (vote)
Target Milestone: ---
Assignee: Digikam Developers
Depends on:
Reported: 2006-06-05 11:04 UTC by Marcus Popp
Modified: 2022-01-26 04:23 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In: 0.9.0

screenshot (220.72 KB, image/png)
2008-12-29 10:32 UTC, S. Burmeister

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Description Marcus Popp 2006-06-05 11:04:19 UTC
Version:            (using KDE KDE 3.5.3)
Installed from:    Ubuntu Packages

It would speed up the raw workflow if you could use the embedded thumbnails of the raw files viewing in Images Editor (and ShowFoto). The -e (extract thumbnail) option is really fast. And the quality of the thumnails getting better and better (I can't see any difference between the raw thumbnail and a jpeg file generated by the camera).
Speed comparision for my NEF Files:
$ time dcraw -2 -w -a -q 0 dsc_0001.nef
    4.36s real     4.01s user     0.35s system
$ time dcraw -e dsc_0001.nef
    0.03s real     0.00s user     0.01s system
The resulting image is just a few pixel smaller:
$ identify dsc_0001.ppm
dsc_0001.ppm PNM 2616x3904 DirectClass 29.2mb 0.370u 0:02
$ identify dsc_0001.thumb.jpg
dsc_0001.thumb.jpg JPEG 3872x2592 DirectClass 682kb 0.980u 0:02
Comment 1 caulier.gilles 2006-06-05 20:27:49 UTC
If you can see a difference, well take JPEG pictures, not RAW.

Your comment is a non sence for me. Please look in the web what is a RAW file exactly (:=)))


Comment 2 Marcus Popp 2006-06-05 22:56:26 UTC
I can see no difference between a jpeg generated (raw+jpeg) and the thumbnail (also jpg) which is integrated in the raw file. The quality of the preview generated by digikam (dcraw -2 -w -a -q 0) isn't very good in the comparison to the embedded jpeg, so why waste time?
If I want to process high quality pictures or change some settings (e.g. white balance) I take the raw and process it with ufraw&gimp.
Comment 3 caulier.gilles 2006-06-05 23:12:43 UTC
gimp support only 8 bits color depth image, digiKam support 16 bits color depth image. This is the difference.

Gilles Caulier

Comment 4 Marcus Popp 2006-06-06 11:56:57 UTC
Digikam doesn't use 16 bit at this point.
But I think the discussion is going in the wrong direction. Should we start an email exchange? If you want I could provide you some test images to substantiate my suggestion.
Comment 5 caulier.gilles 2006-06-06 12:16:18 UTC
When you open a RAW file in editor, the image is decoded in 16 bits / color /pixel depth ! The image is stored like this in memory.

Image editor is not a simple image viewer, it's an editor. When you will apply color filter or transformation and saved it into PNG or TIFF file, the target image is encoded with 16 bits color depth, like UFRAW do !

You talking about a simple image viewer on the screen. This feature is Slideshow kipi plugin, not image editor. And yes, this part must support embeded JPEG into RAW to display image on the screen.

Comment 6 Marcus Popp 2006-06-07 21:56:34 UTC
The 16bit is only for the svn-version true. At the moment i'm stuck with 8bit.

What would be the right application (ImageEditor/ShowFoto/X-Plugin) to see through several hundred raw files and tagging/rating them? I can't do that with the Slideshow-Plugin. Maybe digikam can use a "quick-view" button for imageeditor which make use of the -e option.

thanks for your patience,

Comment 7 caulier.gilles 2006-06-07 22:08:03 UTC
In First, 8 bits only support with RAW can be added into 0.9.0. Actually only 16 bits mode is enable. The code is ready to use 8 bits, only one new option must be add into IOFiles setup dialog page.

About to render RAW files on screen outside editor, if i understand your viewpoint, you would separate viewing and editing features. Right ? but Slideshow is a simple tool to view image... Why not improving this tool to render RAW files using embedded jpeg preview ?

Comment 8 Marcus Popp 2006-06-07 23:03:30 UTC
About the 8bit/16bit you got me wrong I welcome the possibility to use 16bit, but you do no recommend using 0.9.0-svn for production use => i have to go with 8bit at the moment.

I would separate editing (noise reduction, sharpening ...) and rating/previewing images. My current 'workflow' is the following (i shoot raw only):
1. getting the images from cf
(2. backup)
3. sorting out bad images (sharpness, light, different versions of the same images...).  I use the embedded thumbnails (dcraw -e) for the decision.
4. importing it into digikam
5. rating/tagging the image
6. editing images worth editing (e.g. more than 3 stars)
(7. backup again)

I would welcome doing steps 1-3 within digikam and furthermore to combine steps 3 and 5 to one step. I have several other wishes for rating the images (magnifier, light table for comparison of two or three images...) but at this point I'm satisfied with a quick possibility to sort out images or tagging them :-)
Comment 9 caulier.gilles 2006-06-10 13:25:34 UTC
SVN commit 549928 by cgilles:

digikam from trunk : option to toogle RAW decoding picture in 8 bits like digiKam >= 0.8.1 does. This mode is more speed than 16-bits decoding and color correction is automatized by dcraw. 

Use this mode if you don't use ICC color management and if 8 bits color depth is enough for you.

CCMAIL: digikam-devel@kde.org
CCBUGS: 128669, 127991   

 M  +20 -19    libs/dimg/loaders/rawloader.cpp  
 M  +5 -1      utilities/imageeditor/editor/editorwindow.cpp  
 M  +27 -15    utilities/setup/setupiofiles.cpp  
Comment 10 caulier.gilles 2006-06-18 18:56:10 UTC
SVN commit 552644 by cgilles:

digikam from trunk : new fast image preview mode embedded on main interface.

- Separate Preview and Edit of picture. Preview is embedded into main interface, Edit is dedicaced to image editor.
- digiKam album content area can be now toogled between the current image collection thumbs or the current preview of image selected in collection
- To toogle between these views press F3. You can also press ESC to go out of preview mode.
- You can change current image preview using wheel mouse or these keyboard shorcuts : page up, page down, home, end.
- The preview image background use the current color of the selected digiKam theme.
- Preview of RAW files are computed by dcraw using -e option. It's very fast.

There is a screenshot at this url :



- Extract JPEG, PNG, and TIFF preview from Exif Makernote using Exiv2. Need to adapt Exiv2 library for that.
- Loading preview image outside the main interface thread using a new digiKam KIO-Slave.
- Moving keyboard shortcuts of preview widget into main digiKam interface instance to share it with image properties sidebar tabs
- Add RMB menu in this mode or just a link to Edit current image in editor. Need users feedback for that.

CCMAIL: digikam-devel@kde.org
BUG: 127991, 128669, 128914

 M  +2 -2      Makefile.am  
 M  +1 -1      albumiconview.cpp  
 A             albumwidgetstack.cpp   [License: GPL]
 A             albumwidgetstack.h   [License: GPL]
 M  +19 -9     digikamapp.cpp  
 M  +1 -0      digikamapp.h  
 M  +3 -1      digikamui.rc  
 M  +315 -216  digikamview.cpp  
 M  +28 -53    digikamview.h  
 A             imagepreviewwidget.cpp   [POSSIBLY UNSAFE: popen] [License: GPL]
 A             imagepreviewwidget.h   [License: GPL]
Comment 11 S. Burmeister 2008-12-29 10:31:22 UTC
Is using the fast extraction the reason why the editor shows different colours for RAW pictures compared to the big preview in digikam? You can see the difference in the attached screenshot.
Comment 12 S. Burmeister 2008-12-29 10:32:40 UTC
Created attachment 29718 [details]

the same picture shown in the editor and digikam with different colours