lumakey

Turn certain luma values into transparency.

The filter accepts the following options:

'threshold'

Set the luma which will be used as base for transparency. Default value is 0.

'tolerance'

Set the range of luma values to be keyed out. Default value is 0.

'softness'

Set the range of softness. Default value is 0. Use this to control gradual transition from zero to full transparency.