WaveSpeedAI APIWavespeed AIMolmo2 Video Captioner

Molmo2 Video Captioner

Molmo2 Video Captioner

Playground

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Molmo2-4B Video Captioner: Generate detailed, accurate captions for videos with customizable detail levels (low, medium, high). Open-source vision-language model with temporal understanding capabilities. Ready-to-use REST API, no cold starts, duration-based pricing.

Features

Molmo2 Video Captioner

Molmo2 Video Captioner is an intelligent video understanding model that generates detailed captions and descriptions for video content. Upload a video and receive natural-language descriptions of scenes, actions, objects, and events — with adjustable detail levels to match your workflow needs.

Perfect for content creators, accessibility teams, and developers building video understanding pipelines.


Why Choose This?

  • Adjustable detail levels Choose from low, medium, or high detail to control caption depth — from quick summaries to comprehensive scene breakdowns.

  • Scene-aware captioning Understands context, actions, objects, environments, and temporal flow to produce coherent, meaningful descriptions.

  • Flexible video input Accepts video uploads or public URLs for seamless integration into existing workflows.

  • Fast processing Optimized for quick turnaround while maintaining caption accuracy and coherence.

  • Production-ready API Ready-to-use REST endpoint with predictable per-second pricing and no cold starts.


Parameters

ParameterRequiredDescription
videoYesInput video (upload or public URL)
detail_levelNoCaption detail: low, medium (default), or high

Detail Level Options

  • Low — Brief, high-level summary of the video content
  • Medium — Balanced description with key scenes and actions (default)
  • High — Comprehensive breakdown with fine-grained details

How to Use

  1. Upload your video — drag and drop a file or paste a public video URL.
  2. Select detail level — choose low, medium, or high based on your needs.
  3. Submit — the model processes the video and returns a caption.
  4. Use the output — integrate captions into your content, accessibility tools, or data pipelines.

Pricing

Per-5-second billing with a 5-second minimum.

Video DurationCost
Up to 5s$0.005
10s$0.01
30s$0.03
60s$0.06
120s (max)$0.12

Billing Rules

  • Minimum charge: 5 seconds ($0.005)
  • Rate: $0.001 per second ($0.005 per 5 seconds)
  • Maximum video length: 120 seconds (2 minutes)

Best Use Cases

  • Accessibility — Generate video descriptions for visually impaired users and screen readers.
  • Content indexing — Create searchable metadata for video libraries and archives.
  • Social media — Auto-generate captions for posts, reels, and stories.
  • Video SEO — Improve discoverability with rich text descriptions for video content.
  • Surveillance and monitoring — Summarize footage for quick review and logging.
  • Education — Describe instructional videos for enhanced learning materials.

Notes

  • If using a URL, ensure it is publicly accessible. A preview thumbnail in the interface confirms successful access.
  • For videos longer than 2 minutes, split into segments and process separately.
  • Clear, well-lit footage yields the most accurate captions.
  • Use high detail level for complex scenes; low detail for quick overviews.

Authentication

For authentication details, please refer to the Authentication Guide.

API Endpoints

Submit Task & Query Result


# Submit the task
curl --location --request POST "https://api.wavespeed.ai/api/v3/wavespeed-ai/molmo2/video-captioner" \
--header "Content-Type: application/json" \
--header "Authorization: Bearer ${WAVESPEED_API_KEY}" \
--data-raw '{
    "detail_level": "medium"
}'

# Get the result
curl --location --request GET "https://api.wavespeed.ai/api/v3/predictions/${requestId}/result" \
--header "Authorization: Bearer ${WAVESPEED_API_KEY}"

Parameters

Task Submission Parameters

Request Parameters

ParameterTypeRequiredDefaultRangeDescription
videostringYes-Input video URL for captioning. Supports common video formats (MP4, MOV, WebM). Maximum 2 minutes.
detail_levelstringNomediumlow, medium, highLevel of detail in the generated caption. Low: brief summary. Medium: balanced description. High: comprehensive, detailed analysis with temporal dynamics.

Response Parameters

ParameterTypeDescription
codeintegerHTTP status code (e.g., 200 for success)
messagestringStatus message (e.g., “success”)
data.idstringUnique identifier for the prediction, Task Id
data.modelstringModel ID used for the prediction
data.outputsarrayArray of URLs to the generated content (empty when status is not completed)
data.urlsobjectObject containing related API endpoints
data.urls.getstringURL to retrieve the prediction result
data.has_nsfw_contentsarrayArray of boolean values indicating NSFW detection for each output
data.statusstringStatus of the task: created, processing, completed, or failed
data.created_atstringISO timestamp of when the request was created (e.g., “2023-04-01T12:34:56.789Z”)
data.errorstringError message (empty if no error occurred)
data.timingsobjectObject containing timing details
data.timings.inferenceintegerInference time in milliseconds

Result Request Parameters

ParameterTypeRequiredDefaultDescription
idstringYes-Task ID

Result Response Parameters

ParameterTypeDescription
codeintegerHTTP status code (e.g., 200 for success)
messagestringStatus message (e.g., “success”)
dataobjectThe prediction data object containing all details
data.idstringUnique identifier for the prediction, the ID of the prediction to get
data.modelstringModel ID used for the prediction
data.outputsstringArray of URLs to the generated content (empty when status is not completed).
data.urlsobjectObject containing related API endpoints
data.urls.getstringURL to retrieve the prediction result
data.statusstringStatus of the task: created, processing, completed, or failed
data.created_atstringISO timestamp of when the request was created (e.g., “2023-04-01T12:34:56.789Z”)
data.errorstringError message (empty if no error occurred)
data.timingsobjectObject containing timing details
data.timings.inferenceintegerInference time in milliseconds
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