SilkDock
APIVideo Generation

Veo 3.1 Fast

Configurable fields and supported values for veo-3.1-fast.

Model ID

veo-3.1-fast

Capabilities

CapabilitySupported value
Text-to-videoYes
Image-to-videoNo
Multi-image / reference videoNo
Start/end framesNo
Motion transferNo
Audio inputNo
Generated audioYes
Resolution720p, 1080p, 4k
Aspect ratio16:9, 9:16
Duration (seconds)4, 6, or 8

Configurable fields

FieldRequiredNotes
modelYesMust be veo-3.1-fast.
promptYesVideo description or transformation instruction.
secondsNoMust use the supported range or fixed values above.
sizeNoLegacy pixel dimensions. Prefer extra_body.resolution and extra_body.aspect_ratio.
extra_body.resolutionNoSelect one supported resolution above.
extra_body.aspect_ratioNoSelect one supported ratio above; omit when the ratio follows the reference image.
extra_body.generate_audioNoWhether to generate audio in the output video. Audio does not change the price.
extra_body.enhance_promptNoPrompt enhancement switch. Defaults to true.

Do not send unsupported audio, frame, reference, or private provider fields. Account availability is determined by the model list API.

Example

{
  "model": "veo-3.1-fast",
  "prompt": "A cinematic tracking shot through a coastal city",
  "seconds": 4,
  "extra_body": {
    "resolution": "1080p",
    "aspect_ratio": "16:9"
  }
}

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