Video background becomes black when using transform or mask

I am new to fusion. Need help.

While adding mask or using transform node and reducing the size of the video, the background becomes black. Even there is other images.

Can you please what I am doing wrong.

You can see both the attached images.

Thanks

You can reduce the alpha of the background in the control panel, that works out the trasnparecy of the Background.

Hope that helps

the problem you encounter comes from the keyer. you create a new alpha but only in the size of the frame. fusion works with an infinite canvas, which isnt transparent through the key.
you should use a "set canvas color" node after the keyer and bring all sliders (RGBA) to 0 (which should be the default setting)
now you also create a transparent canavas around the image size and if you scale or transform the image the black border should be gone

Thank you, Michael!