Additional GStreamer elements

Other required GStreamer elements installation (required for non-flatpak only):

Debian/Ubuntu

sudo apt install \
  gstreamer1.0-plugins-base \
  gstreamer1.0-plugins-good \
  gstreamer1.0-plugins-bad \
  gstreamer1.0-gl \
  gstreamer1.0-libav \
  gstreamer-vaapi

Fedora

Enable RPM Fusion and run:

sudo dnf install \
  gstreamer1-plugins-base \
  gstreamer1-plugins-good \
  gstreamer1-plugins-bad-free \
  gstreamer1-plugins-bad-free-extras \
  gstreamer1-libav \
  gstreamer1-vaapi

openSUSE

sudo zypper install \
  gstreamer-plugins-base \
  gstreamer-plugins-good \
  gstreamer-plugins-bad \
  gstreamer-plugins-libav \
  gstreamer-plugins-vaapi

Arch Linux

sudo pacman -S \
  gst-plugins-base \
  gst-plugins-good \
  gst-plugins-bad-libs \
  gst-libav \
  gstreamer-vaapi

When installing from non-flatpak package in order to use VA-API using newer and experimental va plugins make sure you have gst-plugins-bad 1.18+. Due to being experimental, these plugins are disabled by default and can be enabled using GStreamer plugin ranking inside Clapper preferences dialog. For older and more stable VA-API codecs, additionally install gstreamer1-vaapi. Verify with:

gst-inspect-1.0 vah264dec
gst-inspect-1.0 vaapi