aspectRatiostring
Aspect ratio: "16:9", "9:16", "1:1", "4:3", "3:4", "21:9", "auto", "adaptive" (model-dependent). Defaults to "auto" when omitted.
durationinteger
Video duration in seconds. seedance-2-0 / happyhorse-1.0 currently accept ~3–15s (any integer in range). veo-3.1 accepts exactly 4, 6, or 8 (default 4) — other values will be rejected. Defaults to the model's default duration. Call list_models for the current allowed values per model.
firstFramestring
First-frame image to control where the video starts. Accepts public URL or local file path (auto-uploaded). REQUIRED for grok-video (image-to-video only — backend rejects it without a firstFrame). For seedance/happyhorse/veo it is optional: with no first frame they do pure text-to-video.
lastFramestring
Optional last-frame image to also control where the video ends. Used by seedance-2-0 and veo-3.1; happyhorse-1.0 ignores this field. Accepts public URL or local file path. Requires firstFrame to also be provided — passing lastFrame alone is rejected.
modelstringобязательный
Video model ID. Use list_models to see available video models. Common (as of writing): "seedance-2-0" (multi-tier general purpose), "happyhorse-1.0" (cost-effective i2v/t2v), "veo-3.1" (Google Veo with two tiers, 4/6/8s, native audio), "grok-video" (xAI Grok Imagine 1.5 — IMAGE-TO-VIDEO ONLY: firstFrame REQUIRED, pure text-to-video is rejected; native audio; 4-15s; 480p/720p).
promptstringобязательный
The video generation prompt. Describe motion, scene, and style — not just the still image.
referenceVideostring
Optional reference video URL for Seedance 2.0 "video continuation". Must be a publicly accessible HTTPS URL (typically a previous generation result videoUrl); local paths are not supported. Only seedance-2-0 accepts this — passing it with other models will fail. IMPORTANT — prompt requirement: to make the new clip semantically continue the reference, the prompt MUST explicitly say "extend" / "continue" (e.g. prefix with "Extend this video with the following plot:"). Without that, the model treats the video as visual reference only and the new clip may drift from a true continuation. Output behavior: the output is ONLY your duration seconds (4-15s) of new content — the reference video is NOT concatenated into the output. To get a single "original + new" clip the user must stitch them locally. Billing: credits are charged at the With-reference-video rate, with billable_seconds = max(reference_duration + duration, min_billable[duration]). Total cost is often higher than direct generation of the same output length. Always pass referenceVideoDuration alongside this field — omitting it causes underbilling and broken continuation behavior.
referenceVideoDurationinteger
Duration of the reference video in seconds (typically 2–15 — backend validates the current allowed range). REQUIRED whenever referenceVideo is set; if omitted the backend treats it as 0, leading to undercharged credits and misconfigured generation. Pass the actual duration of the clip at referenceVideo.
resolutionstring
Output resolution. Common: "480p" / "720p" / "1080p" / "4k" (model-dependent; e.g. Seedance Pro adds 1080p and 4k, while Fast/Mini are 480p/720p only). Use list_models to see what each model supports. Higher resolutions cost more credits per second.
tierstring
Quality tier — only for models that support tiers. seedance-2-0 accepts "mini" (default, cheapest; 480p/720p, no reference video), "fast" (480p/720p), or "pro" (highest fidelity; native 1080p and 4K); veo-3.1 accepts "fast" (default) or "pro". Tiers may be added by the platform — call list_models to see what each model exposes.
