The phone shot the video, so the phone should be able to speed it up. On both platforms the built-in gallery says no — and it says it quietly, by simply not having the control, which sends most people to an app store for something that watermarks the result.
Here is what each phone can actually do, and the route that needs nothing installed.
iPhone: Photos cannot, with one exception worth knowing
Open a normal clip in Photos, tap Edit, and you get trim handles, filters, crop, rotate and a mute toggle. There is no speed control anywhere in that screen, and no amount of looking will produce one.
The exception is a clip shot in Slo-mo. Those carry a second timeline — a ladder of vertical bars under the filmstrip — and dragging its handles decides which part of the clip plays slowly and which plays at normal speed. That is retiming footage that was recorded slow, not speeding up ordinary footage, and it does nothing for a video you did not shoot in Slo-mo.
iMovie for iOS does have a speed control: put the clip on the timeline, select it, and there is a speed slider with a limited range. It is free and it works. The costs are an app to install, a project to create, and an export step, which is a lot of ceremony for making one clip run faster.
Android: Google Photos cannot either
The Google Photos editor trims, crops, rotates, stabilises and mutes. Like the iPhone’s Photos app, it has no speed control for a video.
Manufacturer galleries are a genuine maybe. Some builds of Samsung’s Gallery and other OEM editors have had speed options and some have not, and the layout moves between versions — so look before you assume, but do not count on it. The Play Store’s video editors mostly do offer speed, and mostly on a subscription, with a watermark on the free tier.
The browser route
This editor runs in Chrome on Android and Safari on iOS. Nothing is installed, nothing is uploaded, there is no account and no watermark: FFmpeg compiled to WebAssembly does the work inside the tab, and the result comes back as a download.
- Open the speed-up page in the phone’s browser.
- Tap the drop zone and pick the clip from Photos, Files, or wherever it lives.
- To speed the whole thing up, add an edit covering the clip. To speed up one stretch and leave the rest alone, drag the handles over just that stretch — that case has its own guide.
- Choose a factor. The presets run from 1.1× to 16×; 2× is the usual “make this watchable”, 8× and above is timelapse territory.
- Tap Apply All Edits and save the file.
The audio comes with it, at the right pitch. Speeding up video by throwing away frames and leaving the sound alone is how you get a silent-film effect or a chipmunk. Here the audio is retimed with FFmpeg’s atempo filter, chained when the factor is outside the range one pass allows, so a 2× clip has speech at 2× that still sounds like the person talking. If you would rather not keep the sound at all, the mute toggle drops it in the same pass — which is what a timelapse usually wants.
Three things to expect on a phone
Memory is the ceiling, not a file-size rule. The input, the working buffers and the output all sit in the tab at once. A clip of a minute or two is comfortable; a long 4K recording is where a laptop earns its keep. The limits are here.
It is slower than a laptop, so stay in the tab. Encoding runs on the phone’s CPU inside a WebAssembly sandbox. Keep the screen on and the browser in the foreground — both platforms suspend background tabs, and a suspended encode is a lost encode.
The first run downloads about 32 MB of engine, cached afterwards. Worth doing on wi-fi.
Which to use
| What you want | Where |
|---|---|
| Speed up an ordinary clip, no install | Browser editor |
| Speed up one section, leave the rest | Browser editor — the gallery apps have no concept of this |
| Retime a clip you shot in Slo-mo | The iPhone’s Photos app, with the ladder slider |
| A speed change inside a bigger project | iMovie on iOS, or a Play Store editor on Android |
| 8× to 16×, audio dropped | Browser editor |
| Slower rather than faster | Slow down a video, and read this first |
The honest summary: the phone in your hand can trim, and that is where both gallery apps stop. Speeding a clip up is one of the few everyday edits that still sends people to an app store, and it does not have to — the same browser that is reading this page can do it, and the file never leaves the phone.