Facetime back-camera Resolution

For Ipads and Iphones. The front-facing camera will allow Facetime resolution of 720p. If the back-camera is 1080p, will Facetime resolution be 1080p while using the back camera, or is there a software limitation preventing the back camera from achieving 1080p? More simply put, what is the maximum resolution available using Facetime and the back camera? I am looking into the viability of using IPads for video calls, but 1080p resolution is required to reduce pixelation of content on dry erase white-boards. 720p is not high enough quality, but 1080p is.

Just because the camera is capable of recording 1080p does not mean it streams at that resolution or the software will allow it. I need to know if Facetime and the back-camera have such limitations.

Thank you,