VFX 101: Graphic overlays


(Herman Wang) #1

This is the seventh of a semi-regular series of columns I’ll be presenting on how to do some basic special effects, for people who have little to no experience. We use these effects quite frequently in our Harry Potter-based web series The Spell Tutor.

This column was written in response to an earlier discussion in this forum, and will demonstrate how to overlay simple graphics onto your footage, which is suitable for:

  • Simulating social media emoji effects as seen on Instagram, etc, which is what I’ll demonstrate today
  • What’s commonly known as “lower thirds”, where information is displayed along the lower third of the screen, as seen on news channels for instance
  • Adding on-screen indicators such as arrows or circles to highlight specific parts of footage

First, you’ll need one image and one clip.

For images, you want a transparency-supporting format. (I usually prefer PNG as it supports high resolution without large file sizes.) What this means is that the parts on the outside of the image are see-through as far as your editor is concerned.
Image

For clips, you want either one that comes with an alpha-channel mask, or one with greenscreen you can process yourself. In today’s example I’ll use a free clip I found.
explosion

To start, just place your main footage in your editor’s timeline. Then place the image on top for a short segment, sized down appropriately.
Timeline 1

At this point, all that will happen is the image will appear in one spot and disappear again, which is not very exciting, so let’s jazz that up a little. Over the timeline of the image, we set different keyframes, which will set the image’s position to different spots. I’ve created this simple set so that the image will zigzag up the screen.

Now when the image appears, it’s in motion and a little more interesting. For a final touch, we’ll throw in the explosion clip. The clip will go between the image and the main footage, and I’ll use chroma key to get rid of the background.
Timeline 3

The final result is a little simplistic, but you can easily touch it up by adding more elements, or more keyframes for additional motion.
Demo Clip


Make a video look like a live stream?
(Herman Wang) #3

(Hailey Harper) #4

This is so helpful! How do I find keyframes, though??? We only have iMovie right now but I think my co-producer is getting Final Cut for her birthday in early February so if iMovie doesn’t have it, do you know how we’d add those on Final cut?


(Herman Wang) #5

If I recall correctly, iMovie is pretty bare-bones and so won’t have keyframes.
I’m not familiar with the Final Cut lineup but Pro has keyframes: https://support.apple.com/kb/PH12628?locale=en_GB&viewlocale=en_US


(Hailey Harper) #6

Perfect, thank you! What program do you use?


(Herman Wang) #7

I use Vegas Pro. It’s not really the industry standard, but it’s just as fully-featured. It was more affordable when it first came out but these days the prices have all equalized somewhat.


(Hailey Harper) #8

Good to know- thank you!


(Hailey Buck) #9

Wait! Imovie actually does have keyframes and a pretty simple way to do what you want (I think). You can only do one image on top of footage at a time but it’s super easy. Here’s a video that explains it pretty simply!


(Herman Wang) #10

Yes, this is indeed keyframes (iMovie has changed a lot since I last saw it :slight_smile: )
It’s a rather primitive implementation, pro-level editors will give you a lot more control over keyframes.