Final Cut Pro X: Stabilization may cause flipped video or black bars along the edges
When a clip has extremely shaky camera motion (for example, quick or unsteady panning), stabilizing the clip may result in black bars along the the edges of the video. In some cases, the video may also appear upside down.
From Final Cut Pro X Help:
Follow these stabilization best practices to avoid video with black bars along the edges or upside down video.
- In the Video inspector, reduce the value in the appropriate smoothing parameter (Transition, Rotation, or Scale) in the Stabilization section.
- Cut the clip with the Blade tool or trim the clip in the Timeline to remove sections with most excessive shake or extreme camera moves. You can locate the sections of excessive shake in the Tags section of the Timeline Index. Click on the individual Excessive Shake tags to select the corresponding ranges in the Timeline.