How do you turn an iPhone screen recording into a PDF?

What the conversion actually involves

“Video to PDF” sounds like a format change. It isn’t. A video is a few hundred frames a second of continuous motion; a guide is a handful of discrete moments. The conversion is a decision about which frames matter, and everything else follows from it.

Three sub-problems, in order:

1. Where are the step boundaries? A ten-second recording of a flow through four screens has four steps in it, but nothing in the file says so. The boundaries have to be found by looking at when the picture changed from one settled state to another.

2. Which frame represents each step? Not the first frame after the change — that one is mid-animation, and the screenshot comes out smeared. The right frame is from the middle of the steady state, after the screen stopped moving.

3. How do the frames become pages? A tall phone screenshot on a Letter page wastes most of the width, so the layout has to earn that space with the caption, the step number, and whitespace that does not read as an accident.

Doing it on the phone

Walkthru does all three on the device.

It decodes the recording once, comparing each frame to the last, and cuts where the picture changed and then settled. It waits out the animation — an iOS push transition runs about 0.35 seconds, a keyboard about 0.25 — before deciding a screen has arrived. Screens that keep moving on their own, like a spinner or a blinking cursor, are recognised as such rather than being mistaken for a step boundary.

Then it pulls a full-resolution still from the middle of each steady state, and hands you a guide: one step per frame, each labelled with what kind of transition it was.

You caption, annotate, redact, and export.

The three PDF layouts

Layout	Best for	What a page holds
One step per page	Following along on a screen while doing the task	A large screenshot, the step number, the caption
Compact	Printing, or a long guide someone skims	Several steps per page, screenshots scaled down
Checklist	Onboarding, audits, anything with a tick box	Step text with a box, screenshots small or omitted

Both US Letter and A4 are available, along with a locale-automatic option that picks whichever your region uses. A cover page and PDF outline bookmarks are optional; on a guide past about fifteen steps, the bookmarks are what make it navigable.

What gets baked in

Markers, crops and redactions are rendered into the exported picture, not stored alongside it as overlays that a PDF reader could turn off. For redaction in particular this is the whole point: the pixels underneath are gone in the exported file, so a recipient cannot recover them.

The redaction is also drawn before the crop is applied, which means cropping is never what conceals something. A crop that a reader can undo is not a security boundary, and building one that looks like it is would be worse than not offering it.