Ghost Car

Hi, Im trying to find the name of the technique used when a video shows, for example, the comparison of a cars racing line choice by having both cars on the same video with one car 'ghosted'. (Finding this really difficult to explain!).

I believe that two videos have been taken with camera in the same place. Then Final Cut Pro has somehow merged the two videos. Im after the name of the technique so I can learn how its done.

Thanks in advance for at least trying to understand what Im on about!

Ghosted makes me think that clip is on top of the stack in the Timeline, and has its opacity reduced.

I don't know for sure what technique works best but I think you could mask one car and overlay it to the other video track.

Ive just done a quick test and that looks like the effect I was after. Thanks!

Should have thought of this earlier but this youtube video shows what I was after at minute 10:00: