FFmpeg Media · FFmpeg

Burn SubtitleNEW

📌 What is this：Add subtitles to a video: soft = a switchable subtitle track (no re-encode); hard = burned into the pixels (permanent, forces a re-encode).

💡 When to use：Use to caption a video. Pick soft to keep a toggleable track; pick hard to always show captions (e.g. short/vertical clips). Recognizes .srt / .ass / .vtt (others treated as .srt); Chinese hard subtitles use a built-in Noto CJK font, no extra config needed.

Endpoints

Usage	Method	Path
Submit task	POST	/v1/ffmpeg/burn_subtitle
Query Result	GET	/v1/ffmpeg/info?id={taskId}

⏱ Recommended polling interval：Poll every 3-5s (response includes progress 0-100) until status = succeeded / failed. status = queued means the task is enqueued and waiting to start (not charged yet) — just keep polling. Single-task timeout is 300s with auto-refund.

Request Parameters

Param	Type	Required	Description
inputUrl	string	Required	Input media URL on a trusted allowlist domain (platform CDN or a trusted-source CDN); upload first to obtain one, or use an asset URL already on a trusted CDN
subtitleUrl	string	Required	Subtitle file URL (trusted allowlist domain); recognizes .srt / .ass / .vtt, other extensions treated as .srt
mode	string	—	Mode: soft (mov_text switchable track, no re-encode, mp4 output) / hard (burned into pixels, video re-encoded, audio copied), default soft
webhookUrl	string	—	Completion webhook URL (optional)

Request Example

curl -X POST https://api.cqtai.com/v1/ffmpeg/burn_subtitle \
  -H 'Authorization: Bearer <API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{ "inputUrl": "https://cdn.novapi.ai/veo31/1788164205419_de868f9d69d445baaf577d42e87a236f.mp4", "subtitleUrl": "https://cdn.novapi.ai/tmp/captions.srt", "mode": "hard" }'
# -> { "code":200, "data":"<taskId>" }

Response Example

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "<taskId>",
    "operation": "transcode",
    "status": "succeeded",
    "progress": 100,
    "resultUrl": "https://cdn.novapi.ai/ffmpeg/xxx.mp4",
    "costPoints": 3,
    "errorMsg": null
  }
}

Billing & Credits

Factor 1.3; 1 min 720P ~ 4 credits (x your user rate). Auto-refunded on failure.