Video Captioner Serverless API

With Video Captioner create accurate, customizable subtitles for your videos effortlessly.

POST /v2/video-captioner · submit + poll
 1# pip install "segmind>=1.1.0"
 2# export SEGMIND_API_KEY="YOUR_API_KEY"
 3from segmind import SegmindClient, InferenceFailed, InferenceTimeout
 4
 5# Async (v2) — recommended for long-running / video models.
 6# run() blocks up to 600s; submit_async + job.wait(timeout=...) sets a longer
 7# deadline and keeps the request_id so you can re-poll later.
 8client = SegmindClient()                      # reads SEGMIND_API_KEY
 9payload = {
10    "MaxChars": 10,
11    "bg_blur": False,
12    "bg_color": "null",
13    "color": "white",
14    "font": "Poppins/Poppins-ExtraBold.ttf",
15    "fontsize": 7,
16    "highlight_color": "yellow",
17    "input_video": "https://segmind-sd-models.s3.amazonaws.com/display_images/hallo_output.mp4",
18    "kerning": -2,
19    "opacity": 0,
20    "right_to_left": False,
21    "stroke_color": "black",
22    "stroke_width": 2,
23    "subs_position": "bottom75",
24}
25job = client.submit_async("video-captioner", **payload)
26print(job.request_id)                         # available immediately
27try:
28    result = job.wait(timeout=900, interval=2.0)
29    print(result["status"])                  # COMPLETED
30    print(result.get("output"))              # model output (e.g. video URL)
31except InferenceTimeout as e:
32    print("still running:", e.request_id)    # re-poll later with this id
33except InferenceFailed as e:
34    print("failed:", e.detail)
35
36# Fast models (<=600s) can use the one-liner instead:
37# result = segmind.run("video-captioner", **payload)

API Endpoint

POSThttps://api.segmind.com/v1/video-captioner

Parameters

input_videorequired
string (uri)

URL of the input video to be captioned

Default: "https://segmind-sd-models.s3.amazonaws.com/display_images/hallo_output.mp4"
bg_bluroptional
boolean

Blur the background colour of the subtitle

Default: false
bg_coloroptional
string

Background color of the subtitles

Default: "null"
Allowed values :
"black""white""grey""red""yellow""blue""green""null"
coloroptional
string

Color of the subtitles

Default: "white"
Allowed values :
"black""white""grey""red""yellow""blue""green"
fontoptional
string

Font for the subtitles

Default: "Poppins/Poppins-ExtraBold.ttf"
Allowed values (11 total):
"Poppins/Poppins-Bold.ttf""Poppins/Poppins-BoldItalic.ttf""Poppins/Poppins-ExtraBold.ttf""Poppins/Poppins-ExtraBoldItalic.ttf""Poppins/Poppins-Black.ttf""Poppins/Poppins-BlackItalic.ttf""Atkinson_Hyperlegible/AtkinsonHyperlegible-Bold.ttf""Atkinson_Hyperlegible/AtkinsonHyperlegible-BoldItalic.ttf""M_PLUS_Rounded_1c/MPLUSRounded1c-ExtraBold.ttf""Arial/Arial_Bold.ttf"+1 more
fontsizeoptional
number

Font size. 7.0 is good for videos, 4.0 is good for reels

Default: 7
highlight_coloroptional
string

Highlight color for subtitles

Default: "yellow"
Allowed values :
"black""white""grey""red""yellow""blue""green"
kerningoptional
number

Kerning (spacing between individual letters or characters) for the subtitles

Default: -2
MaxCharsoptional
integer

Max characters space for subtitles. 20 is good for videos, 10 is good for reels

Default: 10
opacityoptional
number

Opacity for the subtitles background

Default: 0
right_to_leftoptional
boolean

Right to left subtitles, for right to left languages. Only Arial fonts are supported.

Default: false
stroke_coloroptional
string

Stroke color for the subtitles

Default: "black"
Allowed values :
"black""white""grey""red""yellow""blue""green"
stroke_widthoptional
number

Stroke width for the subtitles

Default: 2
subs_positionoptional
string

Position of the subtitles

Default: "bottom75"
Allowed values :
"bottom75""center""top""bottom""left""right"

Response Type

Returns: Video

Asynchronous requests (v2)

Use Async for video, long-running (>~60s), or high-concurrency workloads; Sync is simplest for fast image & LLM calls. Async submits a request and you poll it to completion.

  1. 1
    POST /v2/video-captioner

    Submitreturns request_id, status_url, response_url

  2. 2
    GET /v2/requests/{id}/status

    Polluntil COMPLETED or FAILED

  3. 3
    GET /v2/requests/{id}

    Resultfinal response body

Status states

QUEUEDAccepted, waiting for a worker
PROCESSINGRunning on a worker
COMPLETEDDone — result body is ready
FAILEDErrored (incl. content/RAI blocks)
  • A FAILED request is served as HTTP 422 — the body still carries the error detail.
  • An unknown or expired request_id returns HTTP 404.
  • Results are retained for 1 hour, then expire.
  • Content / RAI blocks surface as FAILED, not a separate state.
  • Track completion by polling the status endpoint.

Common Error Codes

The API returns standard HTTP status codes. Detailed error messages are provided in the response body.

400

Bad Request

Invalid parameters or request format

401

Unauthorized

Missing or invalid API key

403

Forbidden

Insufficient permissions

404

Not Found

Model or endpoint not found

406

Insufficient Credits

Not enough credits to process request

429

Rate Limited

Too many requests

500

Server Error

Internal server error

502

Bad Gateway

Service temporarily unavailable

504

Timeout

Request timed out