What Dronie does to your video, what it never does, and why iOS asks the things it asks. The short version: your clip is processed on your phone and goes nowhere else.
No. Everything, reading the clip, the speed-up, the export, happens on your device. There's no server, no account, and no login. The video only leaves your phone if you choose to share it yourself, with the share sheet.
To read the video you pick, and to save the finished one back. iOS asks for those as two separate permissions. If you'd rather not grant library access at all, you can share a video into Dronie from another app instead, and export it with the share sheet when you're done.
Never. Dronie writes a new video and leaves the original exactly as it was. The trim is non-destructive too, trimming the ends only changes what the export uses, so you can drag the handles back out and get that footage again at any point.
It's kept, all the way through, including under the sped-up middle, and it's pitch- corrected, so a hyperlapsed section doesn't come back chipmunked.
From 1× up to the fastest your clip allows, the ceiling depends on how long the section you've marked is. If you'd rather think in finished length than in multipliers, flip the switch in Settings and the controls let you set a target duration instead, with Dronie working out the speed.
If your video lives in iCloud Photos rather than on the phone itself, iOS has to download the full-quality original before Dronie can work with it. Turn on Settings → Downloads → Always allow on cellular and Dronie fetches it without asking, even on mobile data. It's off by default, so a big clip can't quietly eat your data plan.
There's a single small banner, and nothing else, no interstitials, no video ads. In regions that require it you'll see a consent prompt the first time, and you can change your choice whenever you like from Settings → Manage Privacy Choices.
That's Apple's App Tracking Transparency prompt, and it's entirely your call. Say no and Dronie still works exactly the same, the only difference is that the banner shows less relevant ads.
No account, no sign-up, no subscription. Dronie is free, works offline, and asks for nothing to get started.