Bug 357972 - Video Thumbnails are not produced anymore
Summary: Video Thumbnails are not produced anymore
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Thumbs-Video (show other bugs)
Version: 4.14.0
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2016-01-14 10:31 UTC by Evert Vorster
Modified: 2017-07-27 10:58 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In: 5.0.0


Attachments
Screenshot showing the problem (1.79 MB, image/png)
2016-01-14 10:33 UTC, Evert Vorster
Details

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Description Evert Vorster 2016-01-14 10:31:31 UTC
I noticed a while ago ( two months ) that DigiKam did not mark the video clips with the usual "Filmstrip" effect. Now ( 2016-01 ) the thumbnails are just not produced at all. 


Reproducible: Always

Steps to Reproduce:
1. Save film clips in a directory
2. Point DigiKam at the directory
3. Watch the mplayer process chew away at the clips for a while
4. No update on the thumbnails in the icons

Actual Results:  
Icons are not converted into thumbnails of the clips.

Expected Results:  
Thumbnails, with the usual filmstrip effects
Comment 1 Evert Vorster 2016-01-14 10:33:42 UTC
Created attachment 96631 [details]
Screenshot showing the problem

Screenshot, showing the problem, together with a dolphin view of the same directory, with the proper thumbnails.
Comment 2 Maik Qualmann 2016-01-14 11:32:32 UTC
From README:

digiKam do not have any video thumbnailer. Video support is delegate to KDE. To support Video thumbnails,  please install "ffmpegthumbs" package, which is the kdemultimedia Video thumbnail generator for KDE4 file managers.

Your thumbnails in Dolphin could be loaded from the cache. Appear new video thumbnails in Dolphin?

Maik
Comment 3 Evert Vorster 2016-01-14 11:39:05 UTC
ffmpegthumbs package is installed. 
Dolphin is creating the thumbnails on demand, as I was watching it read the files and pop the thumbnails in over time. 

I'm thinking that this may be more of an Arch issue, as Arch is moving over to QT5, and digikam used to work until a recent system upgrade. 

I am now installing DigiKam 5.0.0 from git.
Comment 4 caulier.gilles 2016-01-14 11:44:51 UTC
exactly.

Dolphin use Desktop standard cache mechanism (PNG thumb file stored in your home dir).

DK do not use this mechanism since a while, but a dedicated database to optimize a lots the space used to store thumbs (wavelets compression) and to be able to show thumbs with disconnected media managed with DK.

In Dolphin, press F5 to refresh video thumbs. Does it work ?

Note : DK and Dolphin share the same engine to extract video thumbs. Engine is provided by KDELibs (as an interface), which use a low level extractor as mplayer (configurable in KDE control panel)

Maik : the video thumb handling is a big mess in KDE and very sensible to system update and settings. With Qt5, we will wait a method to be able to extract video thumb with QtMultimedia. As i know this still in TODO list for Qt team : see on bottom of https://wiki.qt.io/Qt_Multimedia

Gilles Caulier
Comment 5 Evert Vorster 2016-01-14 12:06:51 UTC
When I first navigate to the directory, the thumbnails are generated on demand by Dolphin. 
The video files are 3.5Gb each, so this takes a little while. 

If I then hit f5, I can see the icons instantly refresh, so there must be some caching going on.

When I hit F5 on the directory in DigiKam, I can see the mlayer process start up, and chew through the files, but for some reason the icons are not updated.
Comment 6 caulier.gilles 2016-01-14 13:06:54 UTC
DK has a dedicated DB file named thumbnails-digikam.db.

Remove or rename it (it's safe) and restart DK. It's safe : DB file only contain wavelets compressed files, no other data.

Gilles Caulier
Comment 7 Evert Vorster 2016-01-14 17:52:05 UTC
Hi there. 

I tried removing the thumbnails-digikam.db file, and DigiKam did not re-create the missing thumbnails. 

I did notice that DigiKam 5.0.0 makes the thumbnails properly. 
I encoded all the extra metadata into my images directly, so I am going to start with a clean database on DK 5.0.0

Like I said, Arch is moving away from QT4, so things using it are going to start breaking. I'll just use DK 5.0.0 from git until it's a stable package in Arch. 

Thanks for looking into this, but I think we can close this bug.