camera tracking and roto scoping

Your roto work is fine, and the layering is OK. What you need to do is track the movement of the horizon then add that movement to your fireworks layer.

Unfortunately, you shot probably will not Camera Track. The solution I came up with is:

1. Split the clip twice, once where you want to see the fireworks come into the frame, then when the building obscures the sky
2. Name the layer that is going to have the fireworks visible "stabilized" then motion stabilize that layer. The camera stays fairly level so I picked some spots as far away as possible that I thought would track, then ran the tracker until the spot became unusable, then I held down the Alt/Option key and found another point that looked like it would work. Here's what the track looks like:
   
   You can see the feature region around some white buildings, and you can also see where I moved the feature region to the building and then back again so I could track from the start to the end of the stabilized layer.
3. When I applied the tracker to the shot the horizon stays put so the shot moves out of frame like this:
   
   But that's ok because the next step fixes the problem.
4. Now you add a null and your Fireworks layer to the comp, then move to the first frame of the stabilized layer, position the fireworks layer somewhere close, then you parent both the fireworks layer and the stabilized layer to the null.
5. To remove the motion stabilizing and add the movement in the shot to the fireworks layer select the null and press P to bring up the position property, then select the Stabilized layer and press A to bring up the anchor point, then Alt/Option + Click on the Position stopwatch to start an expression and drag the pickwhip to the Anchor Point of the Stabilized layer. This will remove the stabilization and add the motion to the fireworks layer.
6. The next step is to move to an appropriate point in the timeline and fine tune the position of the fireworks layer and set position and rotation keyframes. Now you can move back and forth in the timeline and make a couple of tweaks to position and rotation to keep the fireworks layer stable. The final comp looks like this:
   I just put a red solid in the shot and drew a few masks to represent the fireworks. It only took a few keyframes to keep the layer lined up with the horizon.
7. All that is left is to put the rotoscoped layer on top of this whole comp so your actor and the building are in front of the fireworks.

There are about a dozen ways to approach this shot. This one only took me about 15 minutes. It still needs some tweaking and the roto layer, and some better fireworks but this shows you a viable workflow.

You'll want to also add some reflections on the building. Any layer you parent to the null will follow the camera move.

Whatever workflow you choose to use the techniques are all the same:

• Trim the shot so you are only doing roto and tracking on the frames that need it
• Motion track the scene to give you position data that you can use to lock the effects layer to the footage
• Apply the tracking position data to the effects (fireworks layer)
• Create a mask for the foreground elements
• Layer the composite

I hope this helps.

Hi there.

After applying the method you posted to me. I just get this result, check the video please,

https://drive.google.com/file/d/1L75NcG7vOgPjUE8F-ue3PWGGDtVAOpWn/view?usp=sharing

the background stays on one position and moves with the camera movement (position changes). I want the footage (Camera) to move, but the flare should look real, like stick to its own place and when the camera moves the flare should hide like in real life when camera position changes the background changes.

how can I do that?

thank you.

all the comps are 2d, It is overlay over the original footage and below the roto footage. please checkout the video.

thank you.