Close, But No Cigar
A quick check in Dolphin's preferences showed that the ffmpegthumbs package seemed to be installed and enabled. So why still no video preview thumbnails?
|Preview video files: close, but no cigar...|
Get the Source, Luke
Some more research turned up this interesting tidbit: missing movie thumbnail in Dolphin Kubuntu 15.10 from ask ubuntu/StackExchange. Luckily, the workaround described there turned out to be right on target. As it seems, Kubuntu still ships without a correctly packaged ffmpegthumbs version from KF5.
So I followed the instructions to fetch the recent source code, compiled it, and installed it. And then ... voilà ... instant success. Dolphin now correctly shows video thumbnails. You don't need to restart Dolphin or your desktop session. Just click on the preview button in Dolphin's toolbar twice, and you should now see video thumbs appearing.
|Video thumbnail in Dolphin.|
In a terminal, simply enter these shell commands (but without the leading dollar signs as these just signal that we're talking about shell commands):
$sudo apt-get install git build-essential cmake extra-cmake-modules kio-dev pkg-config libavformat-dev libavcodec-dev libswscale-devPlease note that there may be another fix instead of getting the source that instead fixes some installation paths, but which I didn't tried:
$git clone git://anongit.kde.org/ffmpegthumbs
$git checkout origin/frameworks
$mkdir -p builddir
$cd builddir && cmake .. -DCMAKE_INSTALL_PREFIX=$(kf5-config --prefix) -DCMAKE_BUILD_TYPE=Release -DKDE_INSTALL_USE_QT_SYS_PATHS=ON
$sudo make install
$sudo ln -s /usr/lib/x86_64-
linux-gnu/ plugins/ * /usr/lib/x86_64- linux-gnu/ qt5/plugins/