I'm using an Arabic VTT UTF-8 subtitle file and on the tv I just see square characters. I tried the same subtitle in UTF-8 and had the same issue. I also tried a few other encodings on SRT like windows-1256 and it still had issues, didn't show squares but showed the wrong characters. On Chromecast the same VTT worked fine.
Is there something I need to do on Roku to tell how to display that subtitle? I don't think I can attach the subtitle file here, can I?