If you are talking about warp stabilizer then the best option is to render your stabilized shot to a production format digital intermediate and do the rest of your composite with the rendered DI. If you're talking about stabilizing then you could duplicate the stabilized layer then pre-compose a copy and do your flip on the copy. This would also work with warp stabilized footage.
Generally if things aren't working the way you expect a pre-comp will fix the problem.
Thanks for your reply.
Unfortunately your suggestion didn't work.
II even tried a Warp Stabilize with the pre-comp and I got the same problem.
Do you have any other suggestions?
If you warp stabilize footage that footage should be the only thing in the comp and then you really should render a DI if you are going to do anything else with the footage. If you drop that footage inside another comp and duplicate it then change the scale of the duplicate comp to -100, 100 it has to flip the footage and retain the stabilization It can't do anything else. The problem with working like this is that warp stabilization loads a ton of information into the project file that causes the file size to explode. Rendering the footage then getting rid of the warp stabilized comp will give you better results all the way around.
Another option would be to take your stabilized comp into another comp and use the mirror option.
I'm still not quite visualizing what you are trying to do. Only the edges of the footage will match up if you flip one copy. If you need another part of the footage to match up when flipped then you must pick the exact spot in the frame where you want the edges to match up, put the edge of a rectangular mask on the footage, then duplicate the footage, flip the footage, then change the mask on the top copy to Subtract. If you are trying to overlap the footage so that an arc matches when flipped then the angle and location of the split must be taken into account.
Show us a screenshot or post the video you're working with and we may be able to help you.
I figured it out!
I knew it was small detail that I was not careful with. Basically the way I was doing it was taking the copied layer and going EFFECT > DISTORT > TRANSFORM: and in there I would scale width to -100.
But I discovered by accident, that going through another path it worked. Ctrl+Click: TRANSFORM > HORIZONTAL FLIP. This works perfectly.
Thank you very much for your available help. I should mention that I'm still learning my way around AE.