What is Grok Imagine 1.0 Video Extend?
Grok Imagine 1.0 Video Extend continues a video you point it at, on xAI's classic 1.0-class video model. Pass the public URL of a clip between 2 and 15 seconds, a prompt for what happens next, and the number of seconds to add, and xAI's Grok Imagine appends a continuation that picks up the motion, lighting, and subject of the final frames.
The model key is xai/grok-imagine-1.0-video-extend. Unlike Grok Imagine 1.5 Fast Video Extend, which continues a Fast task on the 1.5 engine, this route takes any clip from any source, which makes it the way to lengthen Grok Imagine 1.5 Video, 1.5 Lite Video, and Video Edit output.
Key features of Grok Imagine 1.0 Video Extend
Any clip, by URL
The source is a URL, not a Grok task, so videos from other models, earlier edits, or your own footage can all be continued. Upload a file in the playground and it is hosted for you.
2 to 10 new seconds, your choice
Set duration to exactly the length you need; the default adds 6 seconds. The task-ID Extend route offers only 6 or 10.
Prompt-directed continuation
The prompt describes what happens in the new seconds: a camera move, a reveal, a change of action. The model matches the look of the final source frames.
Pairs with Video Edit
Edit a clip into the look you want, then extend the result with the same prompt style, all from URLs.
Predictable billing
Per generated second by source resolution plus a per-second charge for the source clip. The cost is shown in the playground before you submit.
What Grok Imagine 1.0 Video Extend is best for
Lengthening 1.5 Video and Lite output
The only Grok route that continues clips from the official API builds, which the task-ID Extend does not accept.
Reveals and payoffs
Add the beat a clip is missing: the camera pans to the reveal, the subject turns, the door opens.
Stretching footage to a cut length
Extend a 4 second clip to 10 to fill a slot rather than regenerating from scratch.
Sequences from any source
Continue a clip from another model or a phone camera without re-creating the opening in Grok.
Grok Imagine 1.0 Video Extend limitations
Source clips must be publicly reachable and between 2 and 15 seconds long. The extension adds 2 to 10 seconds per call and renders at up to 720p. There is no aspect ratio or resolution field: the continuation follows the source. Only the new seconds are generated; the original part of the clip is returned unchanged.
Grok Imagine 1.0 Video Extend API examples
Call Grok Imagine 1.0 Video Extend from any language by POSTing to /v1/tasks. Full parameter docs live at docs.unifically.com/models/video/xai/grok-imagine-1.0-video-extend.
curl -X POST https://api.unifically.com/v1/tasks \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{
"model": "xai/grok-imagine-1.0-video-extend",
"input": {
"prompt": "The camera keeps panning right to reveal a mountain range",
"video_url": "https://files.unifically.com/your-source-clip.mp4",
"duration": 6
}
}'
Successful submission returns a task_id. Poll GET /v1/tasks/<task_id> or set a callback_url on the request to receive the extended video URL.
FAQs
People also ask about Grok Imagine 1.0 Video Extend
It continues a video from its public URL on xAI's classic (1.0-class) video model. Give it the clip, a prompt describing what happens next, and how many seconds to add (2 to 10, default 6), and it returns the clip with the continuation appended.
xAI's classic Grok Imagine video model, the 1.0 generation, which is the only model xAI runs on its extension endpoint. That is why the output is capped at 720p and why this route is cheaper per second than extending a Fast video by task ID, which continues on the 1.5 engine.
That route takes a task_id, only accepts tasks from Grok Imagine 1.5 Fast Video, continues on the 1.5 engine in 6 or 10 second steps, and keeps the spicy preset. This route takes a video_url, works on any clip from any source between 2 and 15 seconds, adds any length from 2 to 10 seconds, renders on the 1.0 model at up to 720p, and is safe-for-work.
Any public clip between 2 and 15 seconds, including output from Grok Imagine 1.5 Video, 1.5 Lite Video, Video Edit, other models, or camera footage. The output is capped at 720p.
Per generated second at a rate decided by the source clip's resolution (a 480p tier and a 720p tier), plus a small per-second charge for the source video. Adding 6 seconds to a 10 second clip bills 6 generated seconds and 10 source seconds.
Yes, as long as the clip you feed back in is still 15 seconds or shorter. For longer sequences, extend the last segment on its own and join the pieces in your editor.
