I am running the following on Fedora F25 under KDE. smplayer-16.11.0-2 mpv-0.23.0-2
I have no problem to open a title with a non-English name. The relevant portion of the log.
METADATA_COPYRIGHT=${metadata/by-key/copyright:}
INFO_MEDIA_TITLE=${=media-title:}
--term-status-msg=STATUS: ${=time-pos} / ${=duration:${=length:0}} P: ${=pause} B:
${=paused-for-cache} I: ${=core-idle} /home/egreshko/misty/楊秀茵.mkv
Playing: /home/egreshko/misty/楊秀茵.mkv
What is your LANG environment? Mine is...
LANG=en_US.UTF-8