In the iOS(9) camera app the controls overlay does not rotate but when 'Record' is selected the video is outputted with the correct orientation. Has anyone got any ideas how apple implemented this.
You've got a few different options to achieve the same effect:
You can rotate the camera, but keep the UI the same, when the device itself is rotated so that it matches UIDevice.currentDevice().orientation.
You could store the device orientation at the time of capture and then rotate the video afterwards.
You could even set the capture connection of the capture session to match the devices orientation while keeping the preview connection the same. Check this out for a similar question