"H.264 (High Profile) decoder is required to play the file"

I'm trying to play videos I recorded from my mobile phone (the stock video / photo app on a Samsung Galaxy On7). When I click them I get the following error message from Totem on Fedora 28:  > H.264 (High Profile) decoder is required to play the file, but is not installed Clicking "Find in programs" doesn't find an appropriate codec. --- The file tool labels them as "ISO Media, MP4 v2 [ISO 14496-14]". --- This is the error log when I run Totem from the CLI: > ** Message: 12:57:35.979: Missing plugin: gstreamer|1.0|totem|H.264 (High Profile) decoder|decoder-video/x-h264, level=(string)4, profile=(string)high, interlace-mode=(string)progressive, chroma-format=(string)4:2:0, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8 (H.264 (High Profile) decoder)