questions for depth？

[AmorFati2016]

hi ,i run you code and test my own data(iphone6 video fixed paramters ),many question:
1.for self-calibrate.
our self-calibrate result : f=2006.5 but your result is 1278,,,,.how do you get the phone real F value while iphone record the video .
and then,i using Radial distortion and tangential distortion model (k1,k2,k3,p1,p2).but the result is Fx=2084.4 Fy=2067.3. not the 1278.
2.for result
the result refine_xxx.bmp is disparity d not the depth z? z=F*Baseline/d?