Help with Burnin

Two things to check: the format is MP4 or MOV, and the video is 10 minutes or shorter. A longer video, or one in a different container format, is not currently supported.

The first transcription in a language downloads that language's model, which needs a connection. If you are offline, or on a very slow connection, the download can stall. Move somewhere with a connection and try again; once the pack is on the phone, that language never needs to download again.

On-device does not mean bundled with the app. The speech model for each language and the speaker-diarization model are both downloaded once, the first time you need them, and then they run with no connection for every video after that. Nothing about your video is ever part of that download.

Automatic detection is not perfect, especially on short clips or videos with background noise. Use the manual language picker to set it directly.

Gap detection catches most dropped spans, but it only retries a span when its diarization check confirms real speech is there, so a very quiet or heavily overlapping section can still be missed. Use the editor to add the missing caption manually. How gap detection works explains why it is deliberately conservative.

Diarization can misjudge a speaker change on fast back-and-forth or overlapping voices. Edit the caption text directly to remove or move the prefix; it does not need to match automatically once you have corrected it.

That is neighbor-clamping working as intended. A caption cannot be trimmed into the one before or after it, so the neighboring caption's edge is the limit. Trim the neighbor first if you need more room.

Edits auto-save roughly every 600ms as you make them, with no button to press. If you close the app immediately after typing, the debounce window means a very last edit could be right at the edge; giving it a second before switching apps is the safe habit.

Undo history is for the current editing session. Reopening a project starts fresh from what was last saved.

Make sure you selected the crop before checking the preview; switching crop or resolution updates the preview to match. If it still looks off, leave the editor and come back in, which forces a refresh.

4K export is the slowest of the three resolutions and takes noticeably longer than 720p or 1080p on the same video. Give it time; a longer video at a higher resolution can take several minutes.

Exports are saved to your Photos library. Check there if you don't see it where you expected.

Not currently. Burnin's export burns captions into the video file itself rather than attaching a separate subtitle track.

If the original source file is no longer where Burnin expects it, it tries to recover it from your Photos library automatically. If the video has also been deleted from Photos, it cannot be recovered.

No. Projects are stored locally on each device with no cloud sync and no account to sync them to. A project made on one iPhone stays on that iPhone.

Deleting a project is immediate and there is no undo for it. The original video, if it's still in your Photos library, is unaffected; only the Burnin project, its captions and its edits are gone.

No. There is no account in Burnin at all, and nothing requires one.

No advertising, no advertising identifier and no third party analytics. The privacy policy says what leaves your phone and when, line by line.

There is no subscription, and every export resolution currently works with no paywall. A future one-time purchase for something added is possible, but there is no ongoing charge.