okay, have a look at these screencaptures: Here is the result of combining the image over a white background in the compositor with and without the pre-mulitplication checked on the alpha over node.
I’m not an expert and this subject really confuses me, but this is where the problem is.
This problem will be the same regardless of the format, quicktime, tga or png.
So in order to display the image properly in Final Cut you would have to change the alpha type, you can do this in Final Cut and this link shows you how:
Scroll down to where it says Changing a Clip’s Alpha Channel Type
After following the instructions, set the alpha channel to black.
This is new information to me, I don’t usually export files with alpha channels. But apparently there are different types of pre-multiplied alpha channels. Looks like I’m going to have to do some research on that.
That should do the trick.
I don’t know why blender exports the image with no file extension, but you could always add an extension, (.tga) and then it should open in any image program.