Requirements for CRT / call recording:
The CRT effect requires that /system/lib/libsurfaceflinger.so is prepared for this effect. Many phones produce flickering for the CRT off effect. The CRT on effect and rotation awareness is isn't included in the normal library.
Patching the library is much work and unfortunately the library cannot be transferred to other ROMs or phones in most cases.
If you have a stock-based ROM for your I9100, you can push the library from the attached zip to /system/lib at your own risk (if you don't know how to undo it if you get a bootloop, don't do it).
For the I9300, the library can be found here.
For other phones/ROMs/versions: Sorry, I'm not planning to patch more libraries.