Alignment errors build up over time -- there is a good 1.5 ft misalignment visible here: https://youtu.be/C6-xwSOOdqQ?t=216

Alignment and scale drift is usually solved via loop closure. Clearer example in the LSD-SLAM: https://www.youtube.com/watch?v=GnuQzP3gty4&feature=youtu.be....

By the way it seems like the researcher behind DSO and LSD-SLAM is now at oculus research! http://vision.in.tum.de/members/engelj

Impressive. I am guessing this is what the next Google Street View will look like.