Burn Subtitles

Permanently render (hard-code) subtitles from an SRT, VTT, or ASS file onto every frame of a video.

API Endpoint

POST /api/v1/tools/burn-subtitles

Accepts multipart form data with a video file and a subtitle file. This is an async endpoint - it returns 202 Accepted immediately and progress is streamed via SSE at GET /api/v1/jobs/{jobId}/progress.

Parameters

Parameter	Type	Required	Default	Description
fontSize	integer	No	24	Subtitle font size in pixels (8-72)

Example Request

curl -X POST http://localhost:1349/api/v1/tools/burn-subtitles \
  -H "Authorization: Bearer si_your-api-key" \
  -F "[email protected]" \
  -F "[email protected]" \
  -F 'settings={"fontSize": 28}'

Example Response

{
  "jobId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "async": true
}

Notes

• Upload two files: the first must be a video, the second must be a subtitle file (.srt, .vtt, or .ass).
• Burned subtitles are permanently part of the video and cannot be turned off by the viewer. For toggleable subtitles, use the Embed Subtitles tool instead.
• Progress updates are available via SSE at GET /api/v1/jobs/{jobId}/progress until the job completes.