Rendering to RGBA (PNG Sequence), what do I need to make this work?
I am trying to use DiffKey to perform some compositing, and it gets me most of the way there, but the result has some unintended objects that need edited out. I can easily do this in GIMP, but I cannot get any output to actually render to RGBA.
My project format settings are using "RGBA-8 Bit", and I am rendering to "PNG Sequence" format, with "Use Alpha" checked in the Video Configuration dialog. The outputted PNGs have no alpha information from the DiffKey as I had hoped, the transparent areas are simply black. It does end up with an alpha channel if I check the box, but it is not useful being all-opaque. Is there something else I need to do to get alpha with the output?
I have tested importing PNG with alpha, and that does appear to work; it is strange, then, that I cannot seem to output alpha.
I am not specifically attached to cinelerra (or gimp) for this task; I would like to know how to do it here, but am also open to other suggestions if there is an easier way to do this.