If you haven’t seen the initial test of an animated matte, let me refresh your memory. As can be seen, the animation worked just fine, but the keying of the matte presented problems. Note, specifically, the white halo which is no longer present.
I will admit that I was not entirely scientific in my approach to fixing it, in that I tried way too many things without intermediary documentation. Given how difficult it is to work in Linux with unfamiliar software that keeps not. Doing. WHAT. I. TELL IT TO DO. GAH.
Given all that, I regret nothing. The two major changes between the original and this current test were simple enough, though. First, I changed the animation from white shapes on black to full green on black. I remain unconvinced that this is entirely necessary. Keying is about contrast, and there is no sharper contrast than white and black. Then again, if I were to try to use the mattes to key out a person, full green or blue would probably be an asset.
As I say that, I can’t really think of a scenario where it would matter. It isn’t like I’d be filming a person against a human-sized version of the animation. Whatever, just make sure your matte and field contrast with each other.
The other, much more important change was how I handled the layer effects in Cinelerra. First and foremost, Cinelerra is weird. Ok? It’s just… weird. Once you get how it wants you to do things, it makes a certain amount of sense, but my experience with Final Cut Pro and Adobe Premiere suggests that it could make things a little easier on the Editor. Case in point: time remapping. The effect for that is “ReframeRT”, which I would not have known about except for the powers of Google. Once applied, though, it does not change the length of your clip as it appears in the timeline. Rather, you have to drag the length of the effect to however long or short you want the remapped clip to play. Don’t get me started on the process of doing that with or without affecting every other effect on the layer.
I digress. In the previous clip, I tried to blur the matte before applying the Key, then blurred it some more. This time I put the Key in before I touched anything else. Note that using the “Chroma Key (HSV)” effect instead of the “Chroma Key” effect gives you much more control, and is my recommended filter for the task. Once the key was as close to perfect as I could manage, I applied a Hue/Saturation filter, in which I pulled Value and Saturation down as far as they would go. If you disable the Chroma Key, you’ll see that you are left with a black image, but since the Key goes in first, Cinelerra (and any other compositor, I expect) reads the contrast first, then darkens in.
Compositing magic, people. Love it.
After that, I applied two blur effects. Cinelerra’s basic Blur allows you to control Vertical and Horizontal somewhat independently. My first blur controlled both to slightly soften the rectangular shapes. The second spoke only to Vertical, and was given key frames to fake a motion blur effect as the shapes slid up and down. There is a “Motion Blur” layer effect, but I couldn’t get it to do anything. It’s definitely worth looking into, as more complicated motions would be nigh-impossible to key frame manually.
Finally, I added garbage mattes to the videos appearing in the left and right squares. These fit snugly over their respective animated rectangles, and were only there to stop the layered videos from bleeding into the other rectangles. Rather importantly, you’ll want to set your matte to “Multiply” instead of “Subtract”. Otherwise, Cinelerra displays everything outside the matte, rather than inside. Every tutorial I found refers to an “Addition” mode, which is not appearing for me, and makes me worry about my installation of Cinelerra, but so far it seems to work.
Voila: a keyed-out animated matte sans the annoying halo effect. I’m still puzzled about cutting out the black background to have one video over another video with the shape intact. I think it would amount to taking my finished animation matte and applying an Invert above the key, effectively creating a holdout matte. I’ll give it a shot, but Cinelerra doesn’t support the nesting of clips, which can be done in Premiere (I don’t know about FCP), or the concept of the precomp, which makes After Effects so very delicious. I predict I’ll end up with an inverted key featuring opaque flying rectangles.
One last thing to note, since I’ve been going on about the order of effects, is how to reorder those effects if you get them wrong. If you’re working with Cinelerra at all, you may have noticed that moving clips, keyframes, and so forth is rather tedious and annoying. Moving effects can be even more so if you need to adjust times and durations, but reordering effects within a layer is as simple as right-click > Move Up or Move Down. Why that isn’t drag-and-drop, I don’t know, but try to remember that you’re working with a surprisingly powerful piece of freeware. I think a little bit of polish missing from the UI should be forgiven at a certain point.
I didn’t do much at all in the Synfig Studio animation suit this time around, as I wasn’t interested in coming up with a whole new animated matte. I will say that it continues to be frustratingly obtuse compared to Illustrator or Flash, but again with the “it’s freeware, be thankful.”
See my Videography Playlist for more experiments.
See you next time!