Issues about UE 4 video output to SDI via AJA KONA 4

Hello UE Staff,

I have encountered some problems recently:

I’m wondering why after I turned the signal into SDI output through AJA KORNA 4 and combined with the live scene, the image and the black/white matte could not match? Please check the video link below:

The other is about performance issues. I played the UE 4 movie on the local machine and the playback rate was as high as 80~90fps, but when I captured the output through the AJA card, the video playback rate dropped to 20~30fps. What could be the cause of this phenomenon? Is it possible to the type of graphics card or setting of AJA? I have tried many times and still can’t solve it. Please check the video link below:

Thank you very much for any feedback and help.