Keying


HitFilm includes several effects for keying your layers.

Keying is the term used for automatically removing parts of an image or video, usually by identifying a specific color.

Chroma UV blur

The UV blur can be essential depending on the way your video camera stores its data.

After keying some video you may notice a pixellated 'stepping' around the edge of the key. If this occurs, add a chroma UV blur before the key itself. This will help to smooth out the edge.

Color difference key

This is used for removing green screen and blue screen backgrounds from video and images.

After selecting the screen color, use the gamma slider to adjust how much is removed. The Min and Max settings are for fine tuning the result, either to remove more of the backgroud or to regain some foreground.

The View matte option is a quick way to see the layer's alpha channel, making it easier to identify areas where the key needs to be cleaned up.

Demult

Quickly key out the background from stock footage shot on black and generate an embedded alpha channel. Very useful for compositing smoke, explosions and similar.

Difference key

Keys areas of a layer based on differences with another layer.

Hue & RGB key

This effect keys the layer based on a color of your choice. You can pick between using the hue or RGB values.

The View matte option is a quick way to see the layer's alpha channel, making it easier to identify areas where the key needs to be cleaned up.

You may get better results using the Color difference key.

Luminance key

This effect keys the layer based on its brightness. This can be particularly useful for sky replacement.