connect PC to Gear VR/Android + Trinus

I want to connect my PC game to Samsung Gear VR, communication managed by the Trinus streamer.
I did a simple pre-test by connecting my Android phone. Everything worked out fine except that the FPS in my game drastically drop from 35 to 15 when streaming to the phone !

Normally a streamer like Trinus just passes on video from the PC to the phone, just the same as when streaming a movie. I therefore don't understand how this can affect the FPS performance in my game.
Anyone with experience with this ?