I've decided to do a little research and I believe i've found the problem.
The hebrew subtitles are provided in LTR format not RTL.
Is there any chance you can add encoding for LTR in ISO 8859-8.
This can be done quite easily using BIDI encoding packages.
ICU4J 49 for Java
GNU FriBidi - for C++
If i've had the code, i'd do it myself :) 10 years of software development.
Hopefully you can add this support.
Please let me know if there something i could do to help.