Was just watching “Chicken Run” and I got curious about the frame-by-frame animation techniques with regard to timing.
In the scene where the chickens are all dancing to the radio, how do they time that with their animation? Is it just a matter of doing the arithmetic, or are there other technicalities to it?
Yes, “arithmetic” is as good a word as any.
The film is shot at a given number of frames per second- as I recall something like 24 or 48, sometimes with a single frame repeated twice before the “next” frame, to reduce flickering.
That’s why videotape seems more “real” than film- it has a higher frame-per-second rate.
Anyway, knowing the frames-per-second, the animators can coordinate the subject’s motions with the tempo of the music. Also with the voices and sound effects.
Also, a particular shot can be edited- remove a frame or two here and there and an action- say stamping a foot or moving a wing- can be more closely aligned with the soundtrack.
And vice-versa; the soundtrack for that shot can be started a few frames earlier or later, and so on.
Sort of. Persistance of vision occurs at 24 frames per second (the last image lingers in the mind while the new image is processed, creating in the mind a smooth transition between the two). Shooting the same frame twice is just a way of halving the amount of work you have to do. Animation is typically shot at 12 double frames per second, with little degradation of smooth motion because the motion is already somewhat irregular to begin with.
Having said that, computer animation is usually 24 frames per second since it’s the computer doing all the work. I don’t know if high budget animation studios might not do 24 frames per second to achieve higher quality; as I recall, Disney does all of its animation at 12 double frames, and no one ever complained.
There was a special for the Making of Chicken Run, where they said the sound is almost always done first, except when they want to tighten the timing of a scene or overdub a sound or speech to give it more punch.