Why are my credits jittering (or stuttering, flickering, pulsing, ringing, strobing)?
Scrolling motion artifacts: they go by different names, but there are two main types. We call them stutter and jitter.
This article will show you how to solve it, but the TL;DR is:
- Slow down your scroll.
- Lower the contrast.
- Never resize renders.
- Seriously, please make sure you're not resizing somewhere in your workflow. It happens all the time!
This will take care 99% of all motion issues.
For a deeper dive, read on.
White text on a black background is as high-contrast as it gets. This creates afterimages on the human retina, which manifest as a stuttering motion.
How to fix it:
Slow it down. The single best thing you can do for your end credits is reduce scroll speed. Our recommended sweet spot is 3 pixels per frame (in 2k or HD) or 6 pixels per frame (in 4k and UHD).
Reduce contrast. Our projects default to 100% white text, but you can set it to any color you like. Alternately, your colorist can dial down the gain in your color session. This is a great option if you want to fine-tune in real time. Don't worry, your text will still read as "white" on the screen.
Take advantage of horizontal space. Credits are often generous with negative space. Re-claim this real estate by adding more columns or even doubling up blocks and placing them side-by-side. This will shorten the overall height of your end credits—and in turn allow you to scroll slower.
Resizing your end credits will create subpixel motion, more commonly called jitter. A picture speaks 1,000 words:
How to fix it:
Don't resize your end credits render. This is easier said than done: if your finishing project is set up in a non-standard size, then resizing occurs whether you know it or not. For example, some projects are set up in 2048x1152 frame size. (We are on record advising against this.) Since there is no "1152p" display standard, your image will be scaled down, either by your DI tool or in the signal path to the display.
Work in uncompressed. While codecs like Apple ProRes and h.264 are powerful and perform well for photographic images, it's important to remember that they are still compressed formats and can introduce small motion artifacts in your scrolling credits.
Don't re-time your end credits after a render. This will not yield you good results. If you need to hit a different TRT, simply return to your Endcrawl renders tab and make another output. Renders are unlimited per project!
Stick with even numbers. While Endcrawl does allow for speeds like 2.5 or 3.5 pixels per frame, we advise sticking to integers. The amount of jitter introduced by half-pixel speeds is very small, so sometimes the tradeoff is worth it. But stick to a speed of 3 or 4 if at all possible.
A word about Fonts
Different fonts perform very differently on the screen. Something that looks gorgeous in large type in print will not have the same effect in smaller point sizes while scrolling. It's especially important to avoid fonts with thin and hairline strokes (for example, thin or light weights of most fonts, as well as many serif fonts).
A word about Computer Monitors
Most consumer monitors refresh at a rate of 60Hz, or 60 times per second. That number does not divide cleanly into 23.98, 24, or 25. Different video frameworks (like QuickTime) will try to compensate for this in various ways. But if you squint hard enough you will see the fudge. Where possible, always review on a professional monitor.
A word on Motion Blur
We advise against adding motion blur to scrolling credits.
This only succeeds in making your credits less legible. Instead, follow the steps outlined in this article to address the underlying issues.