Software update: digiKam 5.4

Version 5.4 of digiKam has been released. This photo management and image editing application for KDE has downloads for Linux, BSD, macOS and Windows. It includes support for various file formats and can also be provided with more options via plug-ins, such as exporting an album to Facebook or Flickr. More about the possibilities of this program is on this page to find. In this release, improvements have been made to the fuzzy sidebar, the similarity search engine and the support for the video files has been completely rewritten.

digiKam 5.4.0 has been released…

This version introduces several improvements to the similarity search engine and a complete re-write of video file support.

Our new contributor Mario Frank has significantly improved the usability of the fuzzy sidebar functionality by offering more information to the user. In duplicates search, every result now contains the average similarity of the potential duplicates to the original. This information can be used to sort the results. The individual elements of the duplicate search result can be sorted by similarity to the original image now, which also works in fuzzy search and sketch search.

Everywhere in the fuzzy sidebar, the table view can now show the precise similarity value to the original image/sketch as column. This option is located in the item properties sub-menu of the column context menu.

Mario has also added the possibility to drag an image that is not imported in digiKam but present on the system (local file) and drop it into the Fuzzy search. This way, similar images can be detected without the need to import them.

In duplicates and fuzzy search, a similarity interval can be specified instead of the minimum similarity. This makes it possible to exclude images with a similarity above the maximum threshold. Using this functionality, the user can exclude a series of nearly identical images, series shots for example. This interval can also be given in the maintenance menu.

Wolfgang Scheffner who works on the comprehensive digiKam handbook has updated most of the menu descriptions. The chapter about the Camera Interface has been replaced by a chapter about the Import Interface. Descriptions of the right sidebar were added and updated. In addition to that, we’ve done a lot of polishing and minor corrections and improvements.

Simon Frei, yet another new contributor, has improved the feature to group images. Grouped items are now processed together. Previously operations would only apply to the top image in the group (ie the image displayed when grouped images are hidden). In other words, applying, for example, a tag to a top image in a group will assign the tag to all images in this group.

Simon has also improved the Batch Queue Manager by adding the ability to process only the current queue. Previously, the “Run” command processed all queues. Now it only processes the current queue. To process all queues, use “Run all”.Maik Qualmann worked on tags to improve the way to manage tag hierarchies, history and completion. He has also fixed several bugs in Flickr and Google export tools available in kipi plugins. As usual he spent a lot of time on improving code elsewhere in digiKam core for better stability.digiKam is now fully ported to the QtAV framework to handle video and audio files. Previously, digiKam 4.x used the Phonon component. Starting with version 5.0.0, digiKam relied on the Qt5Multimedia framework. Both required installing additional codecs by end users for operating systems other than Linux, and using GStreamer in the background for Unix-like systems. The use of extra codecs on MacOS and Windows introduced many differences in media decoding results that depended of codecs supported natively by each platform. The end user was required to solve this problem after installing digiKam. In other words, digiKam wasn’t ready to handle video and audio files right out of the box.

The GStreamer used on Linux posed another problem. From the technical point of view, it’s not easy to deploy and troubleshoot, and there are multiple bugs filed in Bugzilla regarding the missing support of media files in digiKam. Worse yet, even when GStreamer is installed, often Qt5Multimedia refused to work properly. Finally, when the universal AppImage bundling for Linux was introduced few month ago, we often struggled to integrate GStreamer codecs and to have a working version of digiKam with support for media files. This has never been completed due to strange, complex, unsolvable run-time dependencies everywhere. In other words, GStreamer did not work as expected.

Besides the fact that Phonon and Qt5Multimedia rely on extra codecs, the way to extract video thumbnails with this framework is incomplete and unpredictable. This main feature used throughout digiKam to show a fast view of video did not work natively as expected, and thus was not suitable for end users.

The QtAV framework provides the solution to this problem. The framework relies on a comprehensive codecs library and tools from FFmpeg. Codecs are the same across all platforms and the framework API is very similar to the one of Qt5Multimedia. The integration was very fast, and we were able to add new features like video rotation in preview and video slideshow.

The QtAV integration in bundles has been done easily, especially with AppImage. digiKam is now linked to QtAv/libAV instead of using extra run-time dependencies as with Qt5Multimedia. The bundle has been limited to GPL2 codecs from FFmpeg which covers the most frequent video file formats taken with cameras, like MP4, MOV, and AVI containers. GPL2 codecs permits redistribution of bundles everywhere without breaking patent restrictions included in non-GPL codecs from FFmpeg.

In digiKam bundles, we have also introduced the new code from Exiv2 0.26 that has not yet been officially released. As the Exiv2 project takes a while to release this version, we made the decision to use the current implementation. It’s mostly finished, and it introduces improvements to video metadata support as well as fixes for a long list of bugs that have been discovered since the Exiv2 0.25 release. Using Exiv2 0.26 should fix crashes caused by this library that have been reported upstream with previous digiKam versions.

This new digiKam version also includes latest libraw 0.18, whose release coincided with the digiKam release schedule. This version of the raw decoder includes a long list of new supported cameras and fixes several internal bugs reported by digiKam team upstream.For furher information, take a look at the list of more than 200 issues closed in Bugzilla.