Funscripts for JOI

JOI - jerk-off instruction - is paced by what is said, not by what moves. The performer sets the rhythm verbally: faster, slower, stop, hold, edge. That makes it the format where an AI motion tracker has the least to work with, and where a good editor matters most.

Be honest about what the AI can do here

FunGen's AI models track motion. In a typical JOI scene there is very little of it - often a performer talking to camera, largely still. There is no hidden stroke signal in that footage for a tracker to recover, and any tool claiming to fully auto-script JOI from the picture alone is guessing.

So the workflow is different: FunGen gives you a fast way to build the script yourself, rather than pretending to read one off the screen.

Let the audio carry the pace

Where the instruction is delivered over a beat, or the scene uses music to set tempo, FunGen's onset detection reads the audio and lays keyframes on it - with alternate top/bottom or fixed patterns, adjustable sensitivity, and your chosen top and bottom positions. That covers the stroking sections without hand-placing every point.

Chapters are the real tool

A JOI script is mostly structure: a slow section, a faster one, a hold, an edge, a pause, a finish. Mark those spans as chapters and each one gets its own treatment - a stroke rate, a range, or a held position. Building the scene as a sequence of chapters matches how the instruction is actually written, and it makes the script easy to adjust later.

Generate strokes to a rate

Inside any section, parametric stroke generation fills the range for you: give it a BPM for an even rate, or an exact stroke count to fit a span precisely. Ramp the rate across a build, hold at the top for an edge, then resume. This is where most of a JOI script gets written, and it is a few controls rather than a few hundred clicks.

Check it before you play it

The Doctor scores the finished script and flags the problems that matter in this format - gaps where the device does nothing, strokes faster than your hardware can physically follow, and ranges that clip. Fix them in one click, then play to your device.

Start with a scene you know

The full editor, timeline, chapters, stroke generation and Doctor are all in the download. You can evaluate it without an account. Video processing runs on your own machine. Get FunGen and script a scene you already know well; it is the fastest way to learn the workflow.