Try this on your phone: open the camera app, switch to the front-facing camera and wave your left hand. Do you see yourself waving your left hand in the camera app? Good.
Now, record a video while waving your left hand. Watch the recorded video. Does it show you waving your left or right hand? It will show you waving your right hand.
Why is the recorded video flipped?
When you record a video on a front-facing camera, while the live video appears alright, the recorded video is flipped. There is a reason for that — the camera on your device is not a like a mirror but rather like a person looking at you.
From the perspective of a person facing you, your left is their right and vice versa. So, when a camera records, the video turns out flipped i.e. left becomes right and vice versa.
Then, why is the live video correct?
It is a trick used by app developers. People instinctly think of the front-facing camera as a kind of mirror, so they find it awkward when they see the flipped image as seen by the camera. To avoid the awkwardness, app developers (including Outklip) flip the camera image again, to make it look correct.
In summary, the camera captures a flipped image but live video does not appear flipped because of a trick used by developers.