Frame sampling and encoding

Fixed-rate schedules

Offline export uses random-access sampling. For duration \(D\) and integer frame rate \(f\), FixedFPS chooses

\[ N=\max(2, \left\lfloor D f+1/2 \right\rfloor) \]

and includes both endpoints at

\[ t_i = D i/(N-1), \quad i=0,...,N-1. \]

The final timestamp is assigned exactly \(D\) to avoid accumulated floating-point drift.

FixedFPS(fps)

fpsint

A positive integer frame rate.

Produces evenly spaced, endpoint-inclusive sample times for a requested integer frame rate.

Timestamps(stamps)

Validates and stores explicit non-decreasing sample times within the animation duration.

Frame(index, time, progress, snapshot)

One sampled scene paired with its timestamp, duration, and frame index.

GIF centiseconds

GIF stores delays in hundredths of a second. At rate \(f\), KineticKit distributes integer centiseconds by rounded cumulative boundaries:

\[ d_i = round((i+1) 100/f)-round(i 100/f). \]

This alternates neighbouring delays when \(100/f\) is not integral and keeps total drift bounded, unlike independently rounding every frame.

Explicit timestamps

For arbitrary timestamps, delay boundaries are midpoints between adjacent samples, clipped to the animation interval and quantised cumulatively. Minimum-delay rules are checked before bytes are written.

Streaming and determinism

The GIF writer quantises and writes one frame at a time, so memory does not grow with duration. SVG stores analytic motion, while HTML stores the scene, timeline, controls, and accessibility metadata. Every exporter returns a manifest describing the format, dimensions, duration, frame count, fallbacks, and generated assets.

Proposition · Endpoint agreement

All endpoint-inclusive schedulers render the same initial and final scene snapshots as direct calls to Animation.sample(0) and Animation.sample(D).