How to soften the edges of clip?

[sprocket]

Hi members,

Been diggin’ for days on what effect to utilize to soften the hard edges (left and right) of a clip that does not fill the screen. I tried to adjust the image so it fills the screen but the image size does not allow this. The Vignette effect would be a good solution but it does not offer a rectangular shape. See screenshots below. Any solutions would be appreciated. Thank you.

[berndmj]

Use the Alpha Shapes effect with a rectangular shape, adjust the size and position, and play with the Transition Width parameter

[sprocket]

That works! Exactly what I was looking for. The Transition Width made all the difference! Thanks Berndmj!