The hardware at the moment is programmed to average between 10-25fps. This is why 22.25 shows as the framerate. The sensor supports 1080p/60fps on a hardware layer. Maybe when M1cha finishes his [greatly needed] kernel the camera driver can be replaced. The Xperia Z CM 10.2 rom supports shutter speed control for instance. Same camera hardware. Btw, I highly doubt Xiaomi cares to fix this issue.