Alpha Channel in Movie or image sequence node

Hi,

I’m having trouble getting an alpha channel from a movie clip in a compositor movie node. I’ve also tried loading it into the image input node, but still the clip’s alpha doesn’t register in the viewer.

The clip is a simple alpha wipe I created in Apple Motion, and exported as ProRes4444, making sure the export had color and alpha enabled. The clip does as it should in Final Cut, but no joy in the blender compositor.

I know I could find a way to do all this within blender, but I thought it would be simple to create this wipe and drop it in the compositor :frowning:

Any thoughts?


Try using the Alpha socket instead of the image socket.

Steve S

I’ve definitely tried that :slight_smile: but thanks.

I really think I’ve tried all the usual suspects. Guess I’m wondering if this might be a bug.

Has anyone used quicktime .mov files in the movie or image(movie) input nodes and had alpha channels work?

Long time ago but my recollection wss that only the animation codec worked in blender with alpha.

Quicktime support was discontinued a couple of years ago due to licensing incompatibilities.

http://www.blendernation.com/2011/07/13/interview-nathan-letwory-on-the-drop-of-quicktime-in-2-58-2/It may just be that no one updates it.

maybe I don’t get what you are trying to accomplish here but if all you are trying to do is a wipe from one image to another, ( I will assume that the alpha channel matches the BW image) just input the image to the factor socket of your alpha over node to get your wipe.

if that’s not it, a screenshot of your whole node setup would be helpful…

Thanks for the replies guys. Shame about Quicktime support, I had no idea! The clips work ok, but just don’t support alpha? Bummer, as ProRes is a pretty useful codec. I have used the animation codec in the past, so maybe I can give that a go next time.

@gpaprmh I was trying something a bit more tricky than a wipe, involving combining the wipe alpha with other render layer alphas, and then recombing and overlaying a background. In any case, I’ve moved on. I’m just doing it with a wipe object on another render layer now. More flexible in the long run anyway.

Cheers!

@RamboBaby Looking at this article I’m not sure it’s related to my issue anyway. Seems QT has been dropped from Windows builds, but certainly as a movie container it works fine in Blender for me on OS X.

I still might ask a dev about this, cos QT and the Final Cut suite are a pretty solid part of my workflow. And if the movie can be read by Blender, it might not be hard to make its alpha channel accessible too. See how we go :slight_smile: