garageCube

hi there,

this sounds so simple, but i have not yet found the best way to create a round mask. yes, i have created a huge black PNG whith a round hole, and this works.

but it would be much more convinient to have a circle black shape with transparency around it; and invert this mask.

any ideas on that? how to invert the alpha channel on a single layer?

what's wrong with the png you've created if it does the job?
you can't invert non-existent pixels.

if i use a big solid PNG with a transparent hole, there is a limitatiion to scaling and rotation, because at some point the edges of the PNG will be visible.

so it would be more clever to have just a circle shape with transparent suroundings just show whats inside.

just make the png with a bigger space around it, being a still it won't take much cpu.
alternatively make a png or jpg with black and white rather than using an alpha channel and then use the luma key accordingly

Agree with mowgli, make it really big, keep experimenting to find a size that suits.

I made a round mask for a cd launch show which took place in a cinema near me and used it
as a spotlight for the 'tween number announcements, see here:
http://moongold.me.uk/gig/
first clip, about 35 secs in.

Worked a treat. It was 5000 x 3000 if I remember and very small in kb, can't find it
at the mo but a few 100 kb no more. Colour change on auto, movement, great.