--- title: Video Extension product: vercel url: /docs/ai-gateway/modalities/video-generation/video-extension canonical_url: "https://vercel.com/docs/ai-gateway/modalities/video-generation/video-extension" last_updated: 2026-08-24 type: conceptual prerequisites: - /docs/ai-gateway/modalities/video-generation - /docs/ai-gateway/modalities related: - /docs/ai-gateway/modalities/video-generation/video-editing - /docs/ai-gateway/modalities/video-generation summary: Extend existing videos from their last frame with Grok Imagine Video through AI Gateway. install_vercel_plugin: npx plugins add vercel/vercel-plugin --- # Video Extension Continue an existing video from its last frame. Describe what happens next and the model generates new footage that picks up where the source video left off. ## Related pages > **For AI agents:** Follow these links to understand how this page connects to the rest of the Vercel ecosystem. For the full cross-link map (inbound, outbound, prerequisites, and semantic neighbors), see the .graph.md link below. - [Grok Imagine Video on AI Gateway](https://vercel.com/changelog/grok-imagine-video-on-ai-gateway?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [Generate videos with AI SDK](https://vercel.com/kb/guide/ai-sdk-video-generation?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) — Use experimental_generateVideo in the AI SDK to generate videos from a text prompt or an image, set aspect ratio, resolu - [Video Generation with AI Gateway](https://vercel.com/blog/video-generation-with-ai-gateway?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [Video Generation](https://ai-sdk.dev/docs/ai-sdk-core/video-generation?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [AI Gateway now supports asynchronous video generation](https://vercel.com/changelog/ai-gateway-now-supports-asynchronous-video-generation?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [Kling video models on AI Gateway](https://vercel.com/changelog/kling-video-models-on-ai-gateway?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [Grok Imagine Video 1.5 on AI Gateway](https://vercel.com/changelog/grok-imagine-video-1-5-on-ai-gateway?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [generateVideo](https://ai-sdk.dev/docs/reference/ai-sdk-workflow/generate-video?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) - [Text-to-Video Generation](https://vercel.com/docs/ai-gateway/modalities/video-generation/text-to-video?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) — Generate videos from text prompts using Google Veo, KlingAI, Wan, Grok Imagine Video, or ByteDance Seedance through AI G - [Motion Control Video Generation](https://vercel.com/docs/ai-gateway/modalities/video-generation/motion-control?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) — Transfer motion from a reference video to a character image using KlingAI through AI Gateway. - [Reference-to-Video Generation](https://vercel.com/docs/ai-gateway/modalities/video-generation/reference-to-video?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) — Generate videos featuring characters from reference images or videos using Google Veo, KlingAI, Wan, Seedance, or Grok I - [Image-to-Video Generation](https://vercel.com/docs/ai-gateway/modalities/video-generation/image-to-video?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=related) — Animate static images into videos using Google Veo, KlingAI, Wan, Grok Imagine Video, or ByteDance Seedance through AI G Full cross-link map for this page: [/docs/ai-gateway/modalities/video-generation/video-extension.graph.md](/docs/ai-gateway/modalities/video-generation/video-extension.graph.md?from=related&source_path=%2Fdocs%2Fai-gateway%2Fmodalities%2Fvideo-generation%2Fvideo-extension&source_site=vercel-docs&relationship=graph) Every model here also runs as a background job instead of one long-lived request. See [asynchronous generation](#asynchronous-generation) below. ## Grok Imagine Video Grok Imagine Video (by SpaceXAI) can extend existing videos using text prompts. Provide a source video URL and describe the scene that continues from the last frame. To edit an existing video instead of extending it, see [Video editing](/docs/ai-gateway/modalities/video-generation/video-editing). [Browse the latest Grok video models](/ai-gateway/models?providers=spacexai\&capabilities=video-generation) on the AI Gateway Models page. Only `spacexai/grok-imagine-video` supports extension. The `spacexai/grok-imagine-video-1.5` and `spacexai/grok-imagine-video-1.5-preview` models support image-to-video only. > **💡 Note:** Extension requires `providerOptions.spacexai.mode: 'extend-video'`. Setting `videoUrl` > alone triggers [video editing](/docs/ai-gateway/modalities/video-generation/video-editing) > mode, not extension. ### Grok parameters | Parameter | Type | Required | Description | | ----------------------------------------- | ---------------- | -------- | --------------------------------------------------------------------------------------- | | `prompt` | `string` | Yes | Prompt describing what should happen next in the video | | `duration` | `number` | No | Length of the extension segment only, not total output (1 to 10 seconds). Defaults to 6 | | `providerOptions.spacexai.mode` | `'extend-video'` | Yes | Routes the request to video extension instead of editing | | `providerOptions.spacexai.videoUrl` | `string` | Yes | URL of the source video to extend | | `providerOptions.spacexai.pollIntervalMs` | `number` | No | How often to check task status. Defaults to `5000` | | `providerOptions.spacexai.pollTimeoutMs` | `number` | No | Maximum wait time. Defaults to `600000` (10 minutes) | ### Two-step example Generate a source video, then extend it using the ephemeral URL from provider metadata: ```typescript filename="video-extension-two-step.ts" import { experimental_generateVideo as generateVideo } from 'ai'; import fs from 'node:fs'; // Step 1: Generate source video const source = await generateVideo({ model: 'spacexai/grok-imagine-video', prompt: 'A cat sitting on a sunlit windowsill, tail gently swishing.', duration: 5, aspectRatio: '16:9', providerOptions: { spacexai: { pollTimeoutMs: 600000 }, }, }); const sourceUrl = source.providerMetadata?.spacexai?.videoUrl as string; // Step 2: Extend from last frame const extended = await generateVideo({ model: 'spacexai/grok-imagine-video', prompt: 'The cat turns its head, notices a butterfly, and leaps off.', duration: 6, providerOptions: { spacexai: { mode: 'extend-video', videoUrl: sourceUrl, pollTimeoutMs: 600000, }, }, }); fs.writeFileSync('extended.mp4', extended.videos[0].uint8Array); ``` ### Grok example Extend from a fixed source URL: ```typescript filename="video-extension.ts" import { experimental_generateVideo as generateVideo } from 'ai'; import fs from 'node:fs'; const result = await generateVideo({ model: 'spacexai/grok-imagine-video', prompt: 'The cat continues walking slowly through the dandelions as the breeze picks up.', duration: 5, providerOptions: { spacexai: { mode: 'extend-video', videoUrl: 'https://example.com/source-video.mp4', pollTimeoutMs: 600000, }, }, }); fs.writeFileSync('output.mp4', result.videos[0].uint8Array); ``` > **💡 Note:** Video generation can take several minutes. Set `pollTimeoutMs` to at least 10 > minutes (600000ms) for reliable operation. Generated video URLs are ephemeral > and should be downloaded promptly. ## Asynchronous generation Pass a `webhook` factory and the SDK registers your URL with the job instead of polling for it. The factory returns that URL and a `received` promise it waits on, then it fetches the videos itself. ```typescript filename="async-video-extension.ts" const result = await generateVideo({ model: gateway.videoModel('spacexai/grok-imagine-video'), prompt: 'The cat turns its head, notices a butterfly, and leaps off.', duration: 6, providerOptions: { spacexai: { mode: 'extend-video', // Already a hosted URL, which is what the asynchronous flow needs. videoUrl: 'https://example.com/source-video.mp4', }, }, webhook: async () => ({ url: callbackUrl, received: waitForDelivery(token), }), poll: { timeoutMs: 10 * 60 * 1000 }, }); ``` The start request AI Gateway persists is capped at 300 KiB, so pass your source video as a hosted URL on this flow rather than inline data. `token`, `callbackUrl`, and `waitForDelivery` come from [webhook-driven completion](/docs/ai-gateway/modalities/video-generation#webhook-driven-completion), which also covers the receiver, signature verification, and the payload shape. *** --- [View full sitemap](/docs/sitemap)