File formats and limits
Which videos, photos and audio Slicer accepts — formats, sizes, counts, duration and resolution — and the length limits of the finished reel.
On this page
All file limits in Slicer in one place. These are the defaults as of 16.10.2026; if anything changes, the current list is always in the new project wizard under Requirements.
Montage media
What you upload on the wizard's Media step.
| Kind | Formats | Count | File size | Duration and frame |
|---|---|---|---|---|
| Video | .mp4, .mov, .m4v, .webm, .mkv, .avi | up to 10 | up to 2 GB | up to 30 minutes in total; short side at least 360 px, 720p or higher recommended |
| Photo | .jpg, .jpeg, .png, .webp | up to 15 | up to 200 MB | short side at least 200 px |
| Audio | .mp3, .m4a, .aac, .wav, .ogg, .opus, .flac | up to 3 | up to 200 MB | from 3 seconds to 15 minutes |
- Up to 20 files in one montage.
- At least one video or photo is required: a reel cannot be made from audio alone.
- Horizontal videos and photos are reframed to 9:16 automatically.
- Slicer decides by itself which audio is music and which is a voice-over — by whether the recording has speech.
Your own media in the editor
Photos, videos and music you add after the montage — in Media → Add or in the editor.
| Kind | Formats | File size |
|---|---|---|
| Video | the same as montage media; short side at least 240 px | up to 2 GB |
| Photo | .jpg, .jpeg, .png, .webp | up to 200 MB |
| Music | .mp3, .m4a, .aac, .wav, .ogg, .opus, .flac, from 3 seconds to 15 minutes | up to 200 MB |
The finished reel
- AI montage makes a reel up to 90 seconds long. In Reel length you can choose Auto (usually 20–60 seconds) or 15, 30, 60, 90 seconds.
- In the editor you can make the reel longer — for example, by bringing back cut parts or adding clips — but not beyond 180 seconds, otherwise export will not start.
- Aspect ratio — 9:16 by default; in the editor you can choose 4:5, 1:1 or 16:9 (Aspect ratio and cover).
- File — MP4 or MOV, H.264 or HEVC, from 720p to 4K (Export).
How Slicer checks files
Every file is checked twice: by extension — before the upload — and by content after it, to make sure it really is a video, photo or sound. A file that fails the check gets the Upload failed status with a reason: the format is not supported, the file is larger than allowed, the video resolution is too low, the file does not look like a video, and so on.
There are also account-wide limits so the service stays fast for everyone: no more than 40 unfinished uploads at once and up to 60 GB of uploads per day.
Tips for the best result
- Shoot in 1080p — captions and framing will be sharper.
- Speech should be clear, without loud music over the voice — better upload the music as a separate file.
- Talking head — keep the whole face in the shot: the AI keeps it in frame when reframing.
- Several takes of the same line are fine: the director picks the best one.