Hi Samuel,
Dnf info openh264 gives that the version FC33 is installed (!!!) , I heard from other users that they have the same problem sfter upgrading FC38 to FC39 , so I installed the openh264 version FC39 and all runs fine !!
Mayby this can help other Fedora fans to solve the problem.
Thanks for your help.
Regards ,
Ger van Dijck.