Burn-in Subtitles hardcodes your uploaded SRT or VTT onto the owned clip so platforms that need burned captions stay readable without soft tracks.
What does subtitle burn change?
It re-encodes video with the ffmpeg subtitles filter using your uploaded SRT/VTT text and remuxes audio as AAC — captions become pixels in the MP4.
What does hard-burning SRT/VTT change for muted feeds?
Subtitle burn produces hard-burned SRT/VTT captions for platforms that need pixels, not soft tracks.
Concrete results of subtitle burn:
- Uses captions you already have — no Whisper wait.
- Distinct from caption safe margin (padding only).
- Hardsubs survive players that drop soft subtitle tracks.
What happens when soft captions never render on social players?
Without hardsubs, muted viewers meet uploading silent-looking clips when soft captions never render.
What missing hardsubs costs in autoplay:
- Some social players ignore sidecar or soft tracks.
- Teams re-edit in CapCut only to burn the same SRT.
- Safe margin alone cannot create missing caption text.
How do burned captions relate to Shorts and Reels retention?
Burned captions on the MP4 are readable burned captions on owned Shorts and Reels exports.
Why burned pixels beat fragile soft tracks:
- Muted autoplay feeds need burned text for retention.
- Hardsubs travel with the MP4 across apps.
- Pairs with safe margin when UI chrome still clips lines.
- Without burn-in, captions stay fragile soft tracks.
Subtitle burn requires your SRT/VTT — it does not auto-transcribe speech.
When burn captions vs caption safe margin?
Caption safe margin pads the picture so burned text clears UI chrome; subtitle burn creates the burned text from your SRT/VTT file.
Caption and publish path:
Does this auto-transcribe speech?
No — you must upload an SRT or VTT you already have. Whisper auto-captions remain a later GPU-phase tool.
What subtitle burn does not do?
It does not style karaoke word-highlights, translate languages, or keep a separate soft subtitle track — output is hard-burned only.
Subtitle burn hardcodes your SRT/VTT so burned captions travel with every upload.