[FigBug]

It wasn't funny at the time. I helped develop and app + hardware for measuring the force generated when luge / ski cross / boarder cross athletes start. The handles measure the force and sent the data to an iPad which also recorded video.

Worked fine in the office. Every time we went up on the mountain to test, the video didn't work. Go back to the hotel it worked fine.

Whole project was going to fail because of this. Finally it worked once on the mountain, so we proved the system could work.

Finally I found the bug. When setting the video orientation, I was passing in device orientation instead of UI orientation. In my office, I always have my iPad on a stand, so device orientation matched ui orientation and everything worked fine.

When I was on the mountain, I held the iPad flat so I could shield it from the sun with my body, then I'd lift it up when the athlete was about to start. The video would fail to record if device orientation was 'down' since that isn't a valid orientation to rotate video.

I only ended up finding it because I ended up leaving my iPad stand at home one day.