To summarize my fix for similar problems, I did the following: (after enabling both the rpmfusion-free and rpmfusion-nonfree repos as shown here.) sudo dnf install gstreamer1-plugins-ugly vlc gstreamer1-plugins-good-extras ffmpeg livavcodec-freeworld gstreamer1-plugin-openh264 --best --allowerasing
That command installed all the needed codecs and removed the conflicting packages.