Placing a video on top of another video (Picture in Picture)

I need a solution for overlaying a video above another vide and place it in a custom position.

I saw that are nine predefined positions. Can I also set a custom position with x and y coordinates?

See example below:

You can use the offset feature: https://shotstack.io/docs/api

When using offsets you need to use relative positioning not pixels - i.e. 0.1 is 1/10 of the screen width, 0.5 is half screen width. Play about with the offsets and you should be able to achieve the effect you are looking for.

Take a look at the following example:

{
    "timeline": {
    	"background": "#000000",
        "tracks": [
            {
                "clips": [
                    {
                        "asset": {
                            "type": "video",
                            "src": "https://shotstack-assets.s3.ap-southeast-2.amazonaws.com/examples/picture-in-picture/commentary.mp4",
                            "volume": 1
                        },
                        "start": 0,
                        "length": 4.96
                    },
                    {
                        "asset": {
                            "type": "video",
                            "src": "https://shotstack-assets.s3.ap-southeast-2.amazonaws.com/examples/picture-in-picture/commentary.mp4",
                            "volume": 1,
                            "trim": 5
                        },
                        "start": 5,
                        "length": 4.96,
                        "scale": 0.35,
                        "position": "bottomRight",
                        "offset": {
                        	"x": -0.05,
                        	"y": 0.08
                        }
                    },
                    {
                        "asset": {
                            "type": "video",
                            "src": "https://shotstack-assets.s3.ap-southeast-2.amazonaws.com/examples/picture-in-picture/commentary.mp4",
                            "volume": 1,
                            "trim": 10
                        },
                        "start": 10,
                        "length": 2.46,
                        "scale": 0.35,
                        "position": "topRight"
                    },
                    {
                        "asset": {
                            "type": "video",
                            "src": "https://shotstack-assets.s3.ap-southeast-2.amazonaws.com/examples/picture-in-picture/commentary.mp4",
                            "volume": 1,
                            "trim": 12.5
                        },
                        "start": 12.5,
                        "length": 2.5,
                        "scale": 0.25,
                        "position": "topRight"
                    }
                ]
            },
            {
                "clips": [
                    {
                        "asset": {
                            "type": "video",
                            "src": "https://shotstack-assets.s3.ap-southeast-2.amazonaws.com/examples/picture-in-picture/code.mp4"
                        },
                        "start": 5,
                        "length": 10
                    }
                ]
            }
        ]
    },
    "output": {
        "format": "mp4",
        "resolution": "hd"
    }
}

There’s also a demo that gives you the code to do this: Picture in Picture Video Editor Demo — Shotstack