How to add another background in green screen?

[Nemesisjohn]

I'm a newbie in green screen (Premiere) I started a project from scratch. The picture has technically double green screen. If you see the screenshots I added a video in the cellphone screen but the background still in black color with no background at all. I would like to add the purple neon to the background but I don't know if I have to use double ultra key effect or any different effect to do that. When I add the purple picture in a new track everything dissapear and only shows the purple picture. Can anyone help me?

[Richard M Knight]

I would re-shoot with both a green and blue screen.

[smrpix]

Where are you adding the purple neon?  It should be on V1.  But having the single strip greenscreen is kind of janky.  You should also be using corner tracking to insert the sleepy-head clip into the phone

[Nemesisjohn]

For future references, where I supposed to put the purple neon? V1? 

If I make another project , what track I suppose to use for the green screen picture or video?

Where can I fing the corner tracking?

[Sami Succar]

Think of your video tracks like a stack of images. What you put on V1 will be "under" or "hidden" by what you put on V2 and so forth.

So your lowest/farthest background (the purple neon in your case) will go on V1, then the phone on V2, and then the screen on V3.

You'll need to apply the Corner Pin effect on V3, you can find it in the Effects window under Video Effects > Distort, or you can search for in the Effects window (there's a search bar at the top). You'll then need to keyframe the effect so the corners always follow the corner of the phone's screen.

[Richard van den Boogaard]

You need to "tell" PPro what the difference is between the areas that you wish to alter.

Like others have suggested, you can use the corner pin effect to influence the area that is inside the phone. Ideally, you also want to track the movement of the phone and attach it to the footage shown inside the phone. If there is no movement (e.g. it's a still image you're using), simply open up the file in Photoshop to replace the color for the inside of the phone to a blue. Next use another instance of your keyer back in PPro, but use green for the background and blue for the phone footage.

Hope this helps.