Nope, not possible since that's a function of the phone's GPU.
Sure it looks like a camera, but in reality it's just an android phone. If there's no option in the menu (unlikely since it's android), you're out of luck.
Alternative cameras like the 5DmkIII on the other hand will work just fine for livestreaming, but ALL still cameras have limits for video and will reduce quality when they overheat, and some will just shut off. Get a high end webcam like the logitech C930 instead.