hi
I have the same error:
Error parsing option input-file (option not found)
Setting commandline option --input-file=/dev/stdin failed.
Exiting... (Fatal error)
Linux Mint 19.3
SMPlayer v. 19.10.2 (build 9245)
mpv git-2020-04-03-f9cc29e Copyright © 2000-2020 mpv/MPlayer/mplayer2 projects built on Sat Apr 4 00:21:24 UTC 2020
FFmpeg version: git-2020-04-03-a6e56d1