How to load subtitles? Solution and example required. #245

I try to load an external subtitles file like that:

public void setAssFile(File assFile) {
        playbin.set("suburi", assFile.toURI());
        
        Set<PlayFlags> flags = playbin.getFlags();
        flags.clear();
        
        flags.add(PlayFlags.VIDEO);
        flags.add(PlayFlags.AUDIO);
        flags.add(PlayFlags.TEXT);
        
        playbin.setFlags(flags);
}

The 'suburi' returns the good uri for subtitles and when playing the content is transfered to 'current-suburi' perfectly.
At playing 'n-text' is '1' and 'current-text' is '0' (my video source has no subtitles).

But there is no subtitles in video display! How to do it?

Note: I precise that a video source muxed with subtitles displays its default subtitles object during playback.