Understanding FPS, ‘one’s and two’s’ and output

In the world of Animation there is a lot of confusion amongst students and even seasoned professionals when it comes to understanding all the technicalities of frames-per-second, “one’s and two’s” and different video outputs. For this reason I think it might be beneficial if I try and clear up a few misunderstandings. I’ll be covering questions like “What is Animation?” and “At which framerate should I animate?”

What is Animation?

In short, animation is a sequence of images played at a certain rate to create the illusion of movement. The way your eye perceives the movement is something of a phenomena. Some scientists have tried to explain it and there are various myths.. all we know for sure is that humans are given the opportunity to create imaginary moving worlds and that discovery has created a lively art form that is appreciated the world over. The illusion occurs due to the persistence of vision that is caused by the chemical transmission of nerve responses in your eyes. This illusion is determined both by framerate and flicker rate, which are 2 different things. Animation can be achieved with a broad spectrum of media, methods and techniques.

What is FPS/Frames-Per Second?

It is exactly what it implies in the name. It is the amount of image frames that exist in every passing second. In animation anything above 24fps does not necessarily improve the fluidity. You have different standards for every output. Film is 24fps, PAL (European standard for TV) 25fps and NTSC (American standard for TV) 30fps, these are the most common.

Should I be concerned about flicker?

What you need to be concerned of is framerate since flicker rate is affected by the device outputting your animation. The only time flicker rate is something the animator should be aware of is in film when animating below 16 frames per second. Below this threshold the human eye starts to notice a flicker but can still perceive motion down to as low as 10 fps. With computers its different since they don’t use interlacing and most modern screens use 85Hz, as for LCD’s which are usually 60hz or lower it is not a problem as the technology allows a continuous stream of light.

What’s this talk of 1’s and 2’s?

What determines the fluidity is how many of the frames you actually animate uniquely instead of repeating. Most animators animate in 2’s, which means 12 unique frames for every 24 frames. (1..3..4..6..8..10..12) This method of animating is acceptable to viewers and the animation flows pretty nicely. For intense or very detailed animated shots you might want to animate in 1’s as it lets you add more detail. Animators that work with stop-motion animation usually always animate with 1’s because of the medium looking less convincing when animating on 2’s. It is also common with productions that have smaller budgets to animate in 3’s, 4’s, 8’s.. sometimes even more. Typical productions that do this are Saturday morning cartoons and anime. As for computer graphics they almost always animated in one’s. Its known that a lot of Flash animators animate on 1’s but they’re technically animating on 2’s since they’re most likely using the default setting of 12fps, so animating in 2’s would essentially be like animating in 4’s. One of the biggest reasons that Flash animators animate on 12fps is because their output is usually on the web and less frames means smaller file size.

At which framerate should I animate?

My advice is that you always animate at 24fps and then just convert to the other standards accordingly. A well known conversion method for example when going from 24fps to 30fps is called 3-2 pull-down. What happens in this process is that every 4th frame gets printed twice and then a process of field integration is applied where it creates an in-between frame from every 4th frame and from the opposite field of the next frame. Luckily modern methods allow you to use software like After Effects/Premiere that does everything automatically. There are still many debates as to what the best practice is. Some people for example in the 3D industry would rather re-render a scene at 30fps if they’re outputting to NTSC than leaving it for a video editing program. The only problem with this method is that if you have multiple outputs and synchronized sound at a specific framerate you will have to resync it every time otherwise the animation and sound wont fit. It’s up to you to discover a best practice but try keep to the golden rules.

So how many drawings am I supposed to draw per second?

First of all, remember.. there is a difference between drawings and frames.. you’re putting the drawings inside the frames not drawing 24 frames. (Unless you’re animating everything on one’s) Well, if you’re animating everything on 2’s you’ll be sitting with 12 drawings per second, but this is never a concrete thing since its common to add some one’s for those special moments. If after viewing the animation feels as if there is a gap you can go in and make more drawings to make it seem more fluid.

I want my animation to be super smooth to make it realistic, so I’m gonna animate it all on one’s!

This is actually counter productive. Thinking that your animation will benefit from this and that people will end up loving it more is probably not the best way to think. That little bit of smoothness that you gain from a bending cloth will not captivate your audience as much as a good expression or curve. Use moderation and consider rather the principle qualities of animation over buttered movement. Look at a cartoon like the animated Batman series. I’m not sure what they’re animating at but I can tell you its not one’s but its still unbelievably captivating.

Conclusion

There is still so much ground to cover in your animation knowledge than what I’ve shared here but hopefully its given you some perspective and saved you some sleepless nights. If you have any questions feel free to leave a comment. Here are some related links to sites discussing this topic: - Ones and Twos - One’s or Two’s? - Animation Principles - Animation be in 24FPS,25FPS or 30FPS? - Ones or Twos? - On one’s, two’s and three’s