Aliasing artifacts with high-contrast animated text - how to fix?

[lorilinstruth]

HI all,

I recently created a metallic text title in AE, and if I keep it static it looks fine. But I want to add a little tracking expansion animation, and when I do this I end up with weird shimmery artifacts in the thinner high-contrast areas. The project setting is 1080p 25 fps progressive, and the shimmer is there no matter what codec I use to render. I put a little sample here:

sample shimmer aliasing weirdness - YouTube

This sample has a tiny bit of box blur added to it, but you can still see the shimmer in the thinner lines in the M and N. Is there any way to get rid of this annoying shimmer? I've tried the obsolete fx for removing interlacing flicker, several different blurs, duplicating the offending layer and moving it a tiny bit and adjusting its opacity...nothing is working.

This has been a persistent problem for me for a long time now, and I'm finally posting here hoping that there is a simple fix that has eluded all my googling.

Cheers,

Lori

[Rick Gerard · Accepted solution]

Thin lines and video, which is pixel based = aliased edges unless the text precisely lines up with the pixel grid. This is most obvious when the text moves and when the frame rate is below 30 (29.97) fps. There are two easy fixes.

1. Make sure your thin lines are precisely lined up with the pixel grid to start with by using snap to pixel and designing in Illustrator or by examining the AE comp panel with a zoom factor of 800%, then use an expression to move the layer precisely an even number of pixels per frame so the edges don't get re-interpreted.

2. Modify your design so that motion and motion blur hides the problem with thin lines or eliminate the thin lines by choosing a different font.

You should also read these articles from the FAQ. One of the first thing a cinematographer should learn, and it's not taught at all anymore but it is as critical as ever, especially when shooting 24 or 25 fps, is Critical Panning speed. These articles explain what I'm talking about: FAQ: Why does horizontal motion stutter (judder) in my movies, such as during pans?

I forgot to mention compression problems. When you create a movie for YouTube (or Vimeo) these sites will re-compress your video most of the time, even if you send them h.264 compressed to their standards. The problem is that MPEG compression down samples color information and puts that information into square blocks of pixels (8 or 16). When the color differences are extreme, like your nearly white edges and highlights against black, compression is going to make it's best guess for color values and as the pixel values change as the edges appear to move, the compression grid does not change and the pixel grid does not change. This causes some errors in the calculations that often show up as flickering edges with odd color values. You can minimize this problem by using multi pass compression, but you can never make it completely go away. Sometimes you will get a better result if you render a lossless 10 bit or better master and then run that DI (digital intermediate) through the Adobe Media Encoder to compress your MP4 (h.264) for delivery. These problems can also be minimized by modifying your design. Just as in the days before digital video, there are some things that just don't work in video and you have to design around them.

[lorilinstruth]

Thanks, Rick! I'm not sure how I would go about solution 1, so I'll have to go with option 2 - total modification! 🙂 The content of the edit is a lot more important than the titles anyway, so better I spend my available time on that rather than goofing around in AE trying to make pretty things 😉

Thanks for the cinematography info! I mostly film run-and-gun documentary footage, but even then try to pan as slowly as possible when I can. I'm in the EU and film mostly in low light situations with a GH2.

Cheers,

Lori

[Mylenium]

Perpendicular lines will always have antialiasing issues. It's in the nature of the beast - they typically don't cover enough area across multiple pixels to introduce more gradations and may even align so perfectly with the pixel grid that they have hard edges alltogether. Same for motion blur. This is nothing you can solve, even more so with such a slow and static animation. Guess why they use ever so subtle camera moves/ dolly zooms on movie titles? TZhis is realyl only something you can "fix" by changing your procedures or using a different typeface. Conversely your "cheap bevel" could probably be improved with something more finely tuned and avoiding those ugly inset breaks as seen in your clip alone could improve perception as could avoiding the all too busy reflection "light streak" zapping across your text. Again, these are issues with your design that don't play nice with some technical limitations.

Mylenium

[lorilinstruth]

Yeah, the design is pretty sucky...I didn't want to spend time tweaking it until I understood the nature of the problem and what I should be aiming for. It's just a current example of the type of shimmering I've had trouble with in a lot of different contexts with thinner high-contrast areas.

Thanks for the info -- at least I know I'm not missing some magical setting or simple technique 🙂