Honored Contributor
Honored ContributorThe Chroma Key block has a number of different modes of operation so it depends on how you're trying to use it. I've used it to create an alpha channel for a block that did not have alpha to begin with. For example, mixing video with an OSD overlay. The OSD has transparency, the video does not. The Chroma Key block creates an alpha channel for the video so they can be mixed. I believe they refer to this as "constant alpha" since the alpha value is the same for the entire frame. We don't ever change the alpha value in this case, but we could if we needed to. Is that how you're trying to use it or are you trying to peel off the alpha from the source to separate it before it gets to the mixer?
