Does dual-camera recording support time-lapse on iPhone?

What actually makes footage a time-lapse

A time-lapse is not a fast-playback trick applied afterward. It is built at capture by throwing most of the real time away on purpose: instead of writing every frame the sensor produces, the camera keeps only one every so often — a fraction of a second sampled once every second, or every few seconds, depending on how long you plan to shoot — and plays those kept frames back at an ordinary rate. An hour of real time reduced to one frame every two seconds comes out as thirty seconds of video. The compression happens by skipping, not by speeding anything up after the fact.

That is also why a time-lapse has no sound. There was never a continuous audio stream running alongside it to keep — the microphone was idle for nearly all of the time the camera was idle too, so there is nothing to attach to the kept frames.

Why a live compositor cannot skip frames the way time-lapse does

A dual-camera recording is built on the opposite assumption: the frame you see in the viewfinder is the frame that gets written to the file, every time, for the entire take. The GPU draws the front and back images into one composited frame continuously, and the encoder writes each one to disk as it is drawn — there is no point in that pipeline where a scheduler decides to sit idle for a few seconds and only wake up occasionally the way time-lapse capture does. It is a live loop, not an interval timer.

That loop is also already spending the full budget a multi-camera session has. Both cameras run a format that has to support multi-cam simultaneously, and the combined cost of two live streams, a real-time composite and an encoder fills the hardware headroom the session gets — the same ceiling that keeps resolution at 720p or 1080p and frame rate fixed at 30fps rather than offering a faster or slower option. An interval-capture mode is a different kind of job altogether, not a setting away from the one dual-camera recording already runs.

What a long dual-camera take gives you instead

Record a dual-camera take for the length of time you would normally point a time-lapse at — an hour of a room filling up, a sunset, a project taking shape — and you get an hour of ordinary, full-length video, not a compressed clip. Every frame in that hour was actually kept, which is exactly what a time-lapse is built to avoid. Whether the phone can even sustain a take that long comes down to storage and heat rather than anything about time-lapse specifically, and the numbers for that are covered in the guide on how long a dual-camera recording can run.

Getting a time-lapse look into a dual-camera video

Shoot the time-lapse separately, on one camera

The reliable way is two takes: use the stock Camera app's own Time-Lapse mode, on whichever single camera should compress, for the part of the shot that actually needs to speed through time — the crowd filling in, the dough rising, the light changing. Shoot the dual-camera part, wherever your reaction or narration needs both cameras at once, as its own separate normal-speed recording. An editor combines the two afterward the same way it combines any two clips, and each part gets a capture mode built for what it is actually doing.

Speed up a normal dual-camera clip afterward instead

A video editor can play a finished dual-camera clip back faster, and this holds up better than the reverse trick of manufacturing slow motion out of a normal clip. Speeding a clip up only has to discard frames that were genuinely captured — every frame it keeps is real detail, not something the editor invented to fill a gap. It will not match a true time-lapse's ability to compress hours of real time into seconds, because a normal 30fps recording was only ever pointed at a few minutes of footage to begin with, but for compressing a five-minute dual-camera take into twenty seconds of montage, it is a straightforward and honest result rather than an approximation.