Alphas

[micpool]

Hi

I am using ProRes4444 Files with Alpha. These are being incorrectly interpreted in Arena 7.4.0 on a mac.

In this screenshot a feathered red star is composited over a Background. The footage has a Premultiplied (with Black) Alpha. The Clip is set to premultiplied. The output is incorrect because the transparent pixels have a black tinge.

In this screenshot a feathered red star is composited over a Background. The footage has a Premultiplied (with Black) Alpha. The Clip is set to straight. The output is as expected incorrect because the transparent pixels have a black tinge. The Black is deeper than the previous example so seems to have a double error..

In this screenshot a feathered red star is composited over a Background. The footage has a Straight Alpha. The Clip is set to premultiplied. The output is the reverse of what I would expect because it is rendered correctly (i.e this is what I would expect all the outputs to look like, where the alpha type of the footage matches the selection set in the clip alpha) but the clip is set to Premultiplied, not straight.

In this screenshot a feathered red star is composited over a Background. The footage has a Straight Alpha. The Clip is set to Straight. The output is incorrect and the reverse of what I would expect because the transparent pixels have a black tinge.

Is this a bug or am I overlooking something?

Thanks

[Zoltán]

Do you get the looks what you'd expect from any of these, toggling the Alpha type switch?
I mean, does the star look like your footage should?

Could you share the prores file, so we can check it out?

Thanks!