Performed a fresh install of Leap 15.0, and pursued the multilmedia updates (aka: Packman) found in http://opensuse-guide.org/codecs.php.
Results:
linux-4w76:~ # zypper install ffmpeg lame gstreamer-plugins-bad gstreamer-plugins-ugly gstreamer-plugins-ugly-orig-addon gstreamer-plugins-libav libdvdcss2 vlc-codecs
Loading repository data...
Reading installed packages...
'lame' is already installed.
No update candidate for 'lame-3.100-lp150.1.5.x86_64'. The highest available version is already installed.
Resolving package dependencies...
Problem: ffmpeg-3.4.2-lp150.2.1.x86_64 requires libavcodec57 = 3.4.2-lp150.2.1, but this requirement cannot be provided
not installable providers: libavcodec57-3.4.2-lp150.2.1.x86_64[openSUSE-Leap-15.0-1]
libavcodec57-3.4.2-lp150.2.1.x86_64[repo-oss]
Solution 1: Following actions will be done:
do not install gstreamer-plugins-libav-1.12.5-lp150.3.3.x86_64
do not install vlc-codecs-3.0.2-lp150.3.5.x86_64
downgrade of libavcodec57-3.4.4-lp150.9.4.x86_64 to libavcodec57-3.4.2-lp150.2.1.x86_64
install libavcodec57-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libavformat57-3.4.4-lp150.9.4.x86_64 to libavformat57-3.4.2-lp150.2.1.x86_64
install libavformat57-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libavfilter6-3.4.4-lp150.9.4.x86_64 to libavfilter6-3.4.2-lp150.2.1.x86_64
install libavfilter6-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libavdevice57-3.4.4-lp150.9.4.x86_64 to libavdevice57-3.4.2-lp150.2.1.x86_64
install libavdevice57-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libavresample3-3.4.4-lp150.9.4.x86_64 to libavresample3-3.4.2-lp150.2.1.x86_64
install libavresample3-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libavutil55-3.4.4-lp150.9.4.x86_64 to libavutil55-3.4.2-lp150.2.1.x86_64
install libavutil55-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libswscale4-3.4.4-lp150.9.4.x86_64 to libswscale4-3.4.2-lp150.2.1.x86_64
install libswscale4-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libswresample2-3.4.4-lp150.9.4.x86_64 to libswresample2-3.4.2-lp150.2.1.x86_64
install libswresample2-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
downgrade of libpostproc54-3.4.4-lp150.9.4.x86_64 to libpostproc54-3.4.2-lp150.2.1.x86_64
install libpostproc54-3.4.2-lp150.2.1.x86_64 (with vendor change)
http://packman.links2linux.de --> openSUSE
Solution 2: do not install ffmpeg-3.4.2-lp150.2.1.x86_64
Solution 3: break ffmpeg-3.4.2-lp150.2.1.x86_64 by ignoring some of its dependencies
Choose from above solutions by number or cancel [1/2/3/c] (c): 2
Resolving dependencies...
Resolving package dependencies...
The following 65 NEW packages are going to be installed:
gimp-plugin-aa gstreamer-plugins-bad gstreamer-plugins-bad-lang gstreamer-plugins-libav
gstreamer-plugins-ugly gstreamer-plugins-ugly-lang gstreamer-plugins-ugly-orig-addon
libSDL_image-1_2-0 libSoundTouch0 liba52-0 libaa1 libavc1394-0 libbs2b0 libcaca0
libcddb2 libchromaprint1 libdca0 libdvbpsi10 libdvdcss2 libdvdnav4 libebml4 libfaad2
libftgl2 libgme0 libgraphene-1_0-0 libgstadaptivedemux-1_0-0 libgstbadaudio-1_0-0
libgstbadbase-1_0-0 libgstbadvideo-1_0-0 libgstbasecamerabinsrc-1_0-0
libgstcodecparsers-1_0-0 libgstmpegts-1_0-0 libgsturidownloader-1_0-0
libgstwayland-1_0-0 liblilv-0-0 liblrdf2 libmatroska6 libmms0 libmodplug1 libmpeg2-0
libmpg123-0 libofa0 libopencore-amrnb0 libopencore-amrwb0 libopenmpt0 libprojectM-qt5-2
libprotobuf-lite15 libschroedinger-1_0-0 libserd-0-0 libshout3 libsord-0-0 libspandsp2
libsratom-0-0 libsrtp1 libtheora0 libupnp6 libva-wayland2 libvlc5 libvlccore9 libzbar0
vlc vlc-codec-gstreamer vlc-codecs vlc-noX vlc-qt
65 new packages to install.
Overall download size: 13.3 MiB. Already cached: 0 B. After the operation, additional
37.3 MiB will be used.
Continue? [y/n/...? shows all options] (y): y
Selecting option #2 allowed almost all of the updates, EXCEPT ffmpeg.
Attempting to install ffmpeg (3.4.2-lp150.2.1) requires the downgrade of 27 packages. Should the downgrade be performed to install ffmpeg, or is there an alternative?