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Auto-Captioner

Integrate

Model id auto-caption
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/auto-caption?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "video": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"

This request: $0.10 100 API credits Run it on this page

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Utility Video to Video #captioning#video

Adds speech-based captions to a video with adjustable color, font, size, and position

Utility · Data (JSON)

Your first result goes here

Build a request below and run it with your API key. Outputs are copied to our storage, kept forever or 7 days for free.

Build a request

Controls are generated from the model schema. The code and the price update as you change them.

•required video_url
Drop a file, or

Video URL for an audio-containing .mp4 file smaller than 400 MB.

Advanced text_case · txt_color · txt_font · font_size · stroke_width · refresh_interval · left_align · top_align
text_case default default

Choose 'default' to leave subtitle casing as produced by speech recognition. To change it, select 'upper' for uppercase text or 'lower' for lowercase text.

default white

Set the text's color using hexadecimal notation, an RGB tuple, or a color name.

default Standard

Set the caption typeface using a URL pointing to a .ttf file or a built-in font: 'Arial', 'Standard', 'Garamond', 'Times New Roman', or 'Georgia'.

default 24

Text size for the generated captions.

default 1

Text stroke thickness, measured in pixels.

default 1.5

Control how much caption text appears together through its display interval, measured in seconds: keeping captions visible longer shows more text at once.

default center

Align text horizontally using a float between 0.0 and 1.0, or select the named position 'left', 'center', or 'right'.

default center

Align text vertically using a float between 0.0 and 1.0, or select the named position 'top', 'center', or 'bottom'.

POST /run/auto-caption?wait=20 quote → $0.10
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/auto-caption?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "video": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"

Run this request

Your key stays in this browser: it is sent only to the Doitong API and saved (localStorage) only if you tick Remember. Get an API key

About Auto-Captioner

Transcribes audio from an .mp4 `video_url` (under 400MB) and burns captions into the video. Style it with `txt_color`, `txt_font`, `font_size`, `stroke_width`, and `text_case`. Position uses `left_align` and `top_align`. `refresh_interval` of 0.5 to 3 seconds sets how long captions stay on screen.

Parameters

Send either the canonical name or the native name, not both. Canonical names

NameType DefaultAllowed Description
video_urlrequired video
Typeurl · video
Video URL for an audio-containing .mp4 file smaller than 400 MB.
txt_coloroptional
Typestring
Defaultwhite
Set the text's color using hexadecimal notation, an RGB tuple, or a color name.
txt_fontoptional
Typestring
DefaultStandard
Set the caption typeface using a URL pointing to a .ttf file or a built-in font: 'Arial', 'Standard', 'Garamond', 'Times New Roman', or 'Georgia'.
font_sizeoptional
Typeinteger
Default24
Text size for the generated captions.
stroke_widthoptional
Typeinteger
Default1
Text stroke thickness, measured in pixels.
left_alignoptional
Typestring | number
Defaultcenter
Align text horizontally using a float between 0.0 and 1.0, or select the named position 'left', 'center', or 'right'.
top_alignoptional
Typestring | number
Defaultcenter
Align text vertically using a float between 0.0 and 1.0, or select the named position 'top', 'center', or 'bottom'.
refresh_intervaloptional
Typenumber
Default1.5
0.5 – 3
Control how much caption text appears together through its display interval, measured in seconds: keeping captions visible longer shows more text at once.
text_caseoptional
Typeenum
Defaultdefault
defaultupperlower
Choose 'default' to leave subtitle casing as produced by speech recognition. To change it, select 'upper' for uppercase text or 'lower' for lowercase text.
required Canonical name, also accepted

File parameters take a public https:// URL, a data: URI up to 10 MB, or the file_url of an upload. Files

Output

GET /requests/req_8k2m4q7x1z9c3v5b6n0p2r4t
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "auto-caption",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 100,
    "usd": "0.10",
    "charged": 100,
    "refunded": 0
  },
  "input": {
    "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
  },
  "output": {
    "video_url": "string"
  },
  "outputs": [
    {
      "type": "file",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.jpeg",
      "content_type": "image/jpeg",
      "file_size": 1843200,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
Your files, your choiceEvery outputs[].url is a copy on our storage: kept forever (paid per GB-month) or 7 days for free, by your account setting or ?storage=.
Same shape on every modeltype, url, content_type, width, height and duration, for images, video and audio alike. output is the model’s own result object.
Fields of output
video_url
string (video URL)URL pointing to the captioned .mp4 video.

For AI agents: this page as Markdown is at https://doitong.com/en-GB/developers/models/auto-caption.md. All models and guides: https://doitong.com/developers/llms.txt