Rendering to RGBA (...
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Rendering to RGBA (PNG Sequence), what do I need to make this work?

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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.

1 risposta


Maybe I didn't really understand your problem.
I did 2 tests:
1- I created a png image in Inkscape with a transparent background. I imported the image into CinGG without problems (transparent background). I rendered it as png sequence and got a "test.pngs" full of png images (the background remained transparent).
2- I created a new project where I put the clean clip and the related test.pngs. I applied diffKey to "test.pngs" which I put as shared effects on the clean clip. I did a new render with the plugin active and still got a result with the transparent background.

You can try to delete the /home/USER/.bcast5 folder and restart CinGG (maybe it is better if you make a copy of .bcast5, to go back to your steps). Be careful this way you will delete all the configurations you did to CinGG and you will have to do them all over again. But you won't lose the project files, you'll just have to load them again. This way if you have corrupted configuration files you should be able to fix the problem. Otherwise, I can't tell you. Hopefully someone more experienced can help you.

PS: If you have residue that DiffKey couldn't remove, you can try following this tutorial:

andreapaz 07/02/2021 8:16 am

Sorry, wrong link. This is the right one: