VLC Android 2.5.2 cannot display external ass/ssa subtitle with CJK characters correctly

Device: Sony BRAVIA X850D TV
TV OS: Android M
VLC Android Version: 2.5.2

The video file is a .mkv file. All the srt and ass/ssa subtitle file below are UTF-8 encoding.

This TV has a built-in video player. The built-in player can display external srt and ass/ssa subtitle with Chinese characters correctly. But the font size is too small.

VLC Android v2.5.2 can display external srt subtitle with Chinese characters correctly. But it cannot display external ass/ssa subtitle with Chinese characters correctly. It only displays some squares like ☒☒☒☒☒☒☒☒☒☒.

I find some CJK font in the /system/fonts directory of the TV:
NotoSansCJKjp-Bold.otf
NotoSansCJKjp-Light.otf
NotoSansCJKjp-Regular.otf
NotoSansCJKjp-Thin.otf
NotoSansSC-Regular.otf

I read this article. But there is no DroidSansFallback.ttf in the my TV's /system/fonts directory.

And I try to change font name in the ssa/aas subtitle file with 'Noto Sans SC', 'Noto Sans SC Regular', 'Noto Sans CJK JP', 'Noto Sans CJK JP Regular'. But it not works.