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MarkdownLLMs.txt

Veo 3.1

In this page's examples, {BASE_URL} is https://api.uniall.ai.

Veo 3.1 supports text-to-video, image-to-video, first-last-frame generation, multi-image reference generation, and video extension. Use the public model name to select the resolution and speed tier.

Supported Models​

ModelTier
veo3.1-video-720pStandard 720p.
veo3.1-video-1080pStandard 1080p.
veo3.1-video-4kStandard 4K.
veo3.1-fast-video-720pFast 720p.
veo3.1-fast-video-1080pFast 1080p.
veo3.1-fast-video-4kFast 4K.

Endpoint​

POST /v1/video/generations
GET  /v1/videos/{task_id}

Authentication​

Authorization: Bearer sk-***
Content-Type: application/json

Request Parameters​

ParameterTypeRequiredDescription
modelstringYesVeo 3.1 public model ID.
promptstringStrongly recommendedMain prompt. The schema is lenient, but production requests should include it.
imagestringConditionalSingle source image URL for image-to-video.
imagesstring[]Conditional2 to 3 reference image URLs for multi-image reference generation.
last_imagestringConditionalTarget last-frame image URL; use with image.
videostringConditionalSource video URL for extension.
sizestringRecommendedResolution hint, aligned to the selected model tier.
aspect_ratiostringNoText-to-video accepts 16:9 or 9:16. Image-to-video and extension may not honor it.
durationintegerConditionalOutput seconds. Allowed values: 4, 6, or 8. Not used for video extension.
extra_body.generate_audiobooleanNoWhether to generate audio; upstream usually defaults to true.
extra_body.negative_promptstringNoContent to avoid.
extra_body.seedintegerNoRandom seed for reproducibility.

Text-To-Video Example​

curl -X POST "{BASE_URL}/v1/video/generations" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "veo3.1-video-1080p",
    "prompt": "A golden-hour street interview shot, slight handheld movement, natural city ambience, realistic human speech.",
    "size": "1080p",
    "aspect_ratio": "16:9",
    "duration": 8,
    "extra_body": {
      "generate_audio": true,
      "negative_prompt": "watermark, blur",
      "seed": 7
    }
  }'

Image-To-Video Example​

curl -X POST "{BASE_URL}/v1/video/generations" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "veo3.1-video-720p",
    "prompt": "A product slowly rotates on a clean studio desk with soft reflected light.",
    "image": "https://example.com/keyframe.png",
    "size": "720p",
    "aspect_ratio": "16:9",
    "duration": 6,
    "extra_body": {
      "generate_audio": false,
      "negative_prompt": "artifacts, camera shake"
    }
  }'

First-Last-Frame Example​

curl -X POST "{BASE_URL}/v1/video/generations" \
  -H "Authorization: Bearer sk-***" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "veo3.1-fast-video-1080p",
    "prompt": "Transition naturally from the first frame to the last frame, preserving subject identity and camera continuity.",
    "image": "https://example.com/start-frame.png",
    "last_image": "https://example.com/end-frame.png",
    "size": "1080p",
    "aspect_ratio": "16:9",
    "duration": 6
  }'

Task Status And Result​

After creation, save id or task_id, then poll GET /v1/videos/{task_id} until the task reaches completed or failed. See Video Generation Overview for the shared polling interval, status fields, error contract, result URL, and authenticated download flow.

Billing Notes​

Veo billing depends on model tier, speed tier, resolution, output duration, and audio generation. Use task settlement and current product pricing as the final source.

Common Errors​

  • Passing duration outside 4, 6, or 8.
  • Mismatching size with the selected model tier.
  • Expecting aspect_ratio to be honored for image-to-video or extension requests.
  • Sending more than 3 reference images.
  • Passing video without clarifying the extension use case in the prompt or extra body.