Fedora package: Install gstreamer1-plugins-bad-free-extras

For decklinksrc. For Debian/Ubuntu this is already provided by
gstreamer1.0-plugins-bad.
Debian package: Install gstreamer1.0-libav

For the H.264 decoder needed for the Hauppauge HDPVR, the Teradek VidiU,
etc.

Fedora doesn't provide this package for licensing reasons, so you have
to install it manually from rpmfusion.