A Stitch opens your video with up to 5 seconds of someone else's. A Duet records you alongside their video. Both start from the Share to sheet, and each creator chooses who can use their videos this way.
Steps
Stitch
Open the Share to sheet (the Share arrow beside a video, or the Share button on a post screen).
Tap Stitch.
Drag the window to choose up to 5s of their video, then tap Next: Record your part.
Their clip sits first in your strip, marked with scissors. Record your own part, then tap Next.
Trim, add overlays and fill in Details, which shows "Stitching" and their @username. Tap Publish.
Duet
Open the Share to sheet and tap Duet.
Tap the layout button on the right (Left & right to begin with) to pick Left & right, React, Top & bottom, 3 screens or Green Screen. In Left & right, React and Top & bottom, Swap switches the two videos. In React, you can drag your window.
Tap record. Their video plays with you and pauses when you stop.
Tap Next, balance the Original sound and Added sound sliders, then tap Next again.
Trim, add overlays and fill in Details, which shows "Duetting" and their @username. Tap Publish.
Good to know
Only Public videos can be Stitched or Duetted. A Ripple cannot be.
If the creator does not allow it, the Stitch or Duet button is greyed out and the reason is written under the row.
In a Stitch, their clip cannot be deleted, moved from first place or sped up. Your Filters and Background apply to it too.
In a Duet, Speed changes both videos together. Layout and Panes lock once you start recording. Wired earbuds give the cleanest audio.
With 3 screens, tap Panes to set each pane to Original, You or Upload, and record one clip per You pane. With more than one clip, you review each recording with the original and tap Retake or Keep.
Viewers see "Stitch with" or "Duet with" and the creator's @username on your video. Tapping it opens the original. The post is yours, with its own category, audience and Originator claim.
Your defaults live under Settings > Content Preferences, as Stitch and Duet: Everyone, Followers you follow back or Off.
For one video, use Who can Stitch and Who can Duet on the Details screen, or later on your own post's Share to sheet. Use my setting or Use my account setting keeps your default.
Changing a setting affects new Stitches or Duets only. Published ones stay up. It does not apply to you: you can Stitch or Duet your own Public videos.
