Veo3.1 Fast API for Low-Latency AI Video Generation

What is Veo3.1 Fast?

Veo3.1 Fast is a video generation model available on UniAll AI under the public model id `veo3.1-fast-video-720p`. It is designed for faster turnaround on short AI-generated clips while supporting multiple production workflows: text-to-video, image-to-video, first/last-frame generation, reference media to video, and video extension or editing from a source video.

The model is useful when speed and iteration matter: creative testing, social media assets, e-commerce product demos, storyboards, ad variations, and automated content pipelines.

Core capabilities

**Text to video**: generate a short clip from a written prompt.
**Image to video**: animate a reference image with camera movement, scene action, or product motion.
**First/last frame video**: provide a starting frame and ending frame to guide the transition.
**Video to video**: use a source video for editing or continuation-style workflows.
**Reference media to video**: guide the generation with reference assets.
**Async API**: submit a job, poll or retrieve results when complete.
**Optional audio**: enable audio generation when supported by the selected resolution profile.

Supported durations are **4s, 6s, and 8s**. The model supports **16:9** and **9:16** aspect ratios, with selectable output resolutions including **720p, 1080p, and 4K** profiles.

Who should use it?

Veo3.1 Fast is best for:

1. **Marketing teams** testing many short video concepts quickly. 2. **E-commerce operators** creating product reveal clips and lifestyle demos. 3. **Developers** adding AI video generation to SaaS tools, CMS platforms, or automation workflows. 4. **Agencies** producing fast drafts before final creative refinement. 5. **Short-video creators** generating vertical clips, storyboards, or motion concepts.

If you need the highest possible final-detail output, you may compare it with standard Veo3.1 variants. If you need lower latency and lower per-second cost for iteration, Veo3.1 Fast is usually the practical starting point.

API usage

Endpoint:

```http POST /v1/videos/generations ```

Generation is asynchronous. Send a request with the model id, generation mode, prompt, duration, and media inputs required by the selected mode.

Example text-to-video request:

```json { "model": "veo3.1-fast-video-720p", "generation_mode": "text_to_video", "prompt": "A cinematic product reveal of a matte black smart speaker on a glass table, soft studio lighting, smooth dolly-in camera movement.", "duration": 8, "aspect_ratio": "16:9", "resolution": "720p", "generate_audio": true, "video_count": 1 } ```

Example image-to-video request:

```json { "model": "veo3.1-fast-video-720p", "generation_mode": "image_to_video", "prompt": "Animate the product with a slow rotating camera, subtle reflections, premium commercial style.", "image_url": "https://example.com/product.png", "duration": 6, "aspect_ratio": "9:16", "resolution": "720p" } ```

Common generation modes:

| Mode | Required inputs | Typical use case | |---|---|---| | `text_to_video` | `prompt` | Generate a clip from text | | `image_to_video` | `prompt`, `image_url` | Animate a product, character, or scene image | | `first_last_frame` | `prompt`, `first_image_url`, `last_image_url` | Control start and end frames | | `video_to_video` | `prompt`, `video_url` | Edit or extend a source video | | `reference_media_to_video` | `prompt` | Generate using reference media context |

Pricing angle

UniAll AI bills Veo3.1 Fast by generated video seconds. The listed user price for the 720p fast profile starts at **$0.068 per second** without audio and **$0.102 per second** with audio. Higher resolution and audio profiles may cost more; for example, 4K fast generation is priced higher than 720p.

Because billing is per second, cost is easy to estimate:

```text estimated cost = duration in seconds × selected resolution/audio unit price ```

For teams running automated workflows, this makes it practical to control cost by limiting duration, choosing 720p for drafts, and reserving 4K for final assets.

Implementation tips

Use **short, visual prompts** with subject, motion, camera direction, lighting, and style.
Choose **9:16** for TikTok, Reels, Shorts, and mobile-first ads.
Choose **16:9** for website hero videos, YouTube, and product landing pages.
Use image-to-video when brand or product consistency matters.
Use first/last-frame mode when you need a specific transition or storyboard beat.
Handle async status and failed jobs gracefully; UniAll AI supports refund-on-failure behavior for this model.

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常见问题

What is the public model id for Veo3.1 Fast API?

The public model id is `veo3.1-fast-video-720p`. Use it in the `model` field when calling the UniAll AI video generation endpoint.

What generation modes does Veo3.1 Fast support?

It supports text-to-video, image-to-video, first/last-frame video generation, reference media to video, and video-to-video workflows such as editing or extension.

How is Veo3.1 Fast priced?

It is billed per generated second. The 720p fast profile starts at $0.068 per second without audio and $0.102 per second with audio. Final cost depends on duration, resolution, and whether audio is enabled.