SMI are subtitles. How to get korean or other region subtitles working with VLC. The problem is because Unicode fonts on Windows are not installed by default, however on mac they are.
These steps works with both Windows 10 and macOS (OSX):
Go to VLC -> Preferences -> Subtitles/OSD.
1) Set default encoding to the one that is reported by Notepad++ at the bottom right.
2) Set font to "Arial Unicode MS"
In Windows 10 you have to install then manually, the fonts are copyrighted. Microsoft Office and other software install them depending on the program and version. On OSX they in "/Library/Fonts/Arial Unicode.ttf"
https://en.wikipedia.org/wiki/Arial_Unicode_MS
Additionally, you can leave the default encoding to your local or default setting and convert the SMI file to UTF-8-BOM with Notepad++ for example. That way the UTF8 with BOM already has the encoding inside.
Example to test:
https://trac.videolan.org/vlc/ticket/17257
Search too for malgun gothic or batang or gulim fonts.