Five layouts to start from
Single, Stack of 2, Stack of 3, 2-Top / 1-Bottom, and 1-Top / 2-Bottom. Pick a template first, then fill its empty slots.
Polyrhythm Labs · iOS App
Collage
Multi-clip vertical video collages, composed on your iPhone.
Pick a layout, drop in one to three clips, reframe each one in place, trim and sync, then export a single share-ready 9:16 video. Built for Reels and TikTok-style edits — and built to run entirely on your device.
Download on the App Store
Requires iPhone 11 or newer · iOS 26
- 9:16 portrait
- 720p resolution
- H.264 · 30 fps
- 1–3 clips per collage
- 120s max per clip
Features
Reframe in place
Two-finger pan and zoom any clip directly inside its slot. The crop you see is the crop you export — there is no separate editor.
Trim every clip
Set in and out points per clip, up to 120 seconds each. The collage plays through to the end of your shortest clip.
Swap with a long-press
Long-press a slot and drag it onto another to swap the two clips instantly — no menus, no re-importing.
Add a soundtrack
Pick any song from your Apple Music library to play over the collage. Video audio is muted so the track stands on its own.
Auto audio sync — Beta
Collage can line up your clips automatically by analyzing their audio, so movements stay in time. Per-clip confidence, single-frame nudge, and revert.
Preview equals export
The canvas updates live as you edit — no playback needed. What you see is rendered pixel-for-pixel into the final file.
Export straight to Photos
Render a single 9:16 video to your Photos library with real, frame-by-frame progress — never a fake spinner.
Runs entirely on device
No account, no upload, no servers. Every clip, edit, and export stays on your iPhone.
Layouts
Every collage starts from one of five templates. Each slot is filled independently, and clips can be swapped between slots at any time.
How it works
1
Pick a layout
Choose one of five templates. Collage opens the editor with empty slots on a black 9:16 canvas.
2
Fill and reframe
Tap a slot to add a video from your library, then pan, zoom, trim, and swap until each clip sits right.
3
Preview and export
Play the whole collage through, then export a single video straight to your Photos library.
Private by design
Collage has no account, no analytics, no tracking, and no servers. Your videos and music are read, edited, and rendered entirely on your iPhone — nothing is ever uploaded. The App Store privacy label is Data Not Collected.
Read the full privacy policy →Support
Questions, bug reports, or feedback? We read every message.
Visit the support page or email support@twostepapp.com.