Introduction
Video-extend for Veo 3.1 Fast: send a clip, and its last frame becomes the first frame of a new 4-8 second image-to-video segment, returned joined to your original.
| Field | Value |
|---|---|
| Input | Video |
| Output | Video |
| Publisher | |
| Clip length | 4, 6 or 8 seconds; reference images always give 8 |
| Resolution | 720p: 1280x720 (16:9) or 720x1280 (9:16) |
| Aspect ratios | 16:9, 9:16 |
| Frame rate | 24 fps |
| Sound | Generated with every clip |
| Inputs | Prompt; first frame and optional last frame; 1 to 3 reference images |
Key features & highlights
Put the person from one photo into the place from another
Image 1 was a man in a denim jacket at a gas station, Image 2 an observatory at night. The prompt asked the man from the first image to walk up to the observatory, knock on the door and wave. In 8 seconds he did all three, with the same face, hair and jacket. A woman who was also in Image 2 did not appear.
One continuous push-in
From a single first frame and "Slow push-in", the camera moved in without a cut over 8 seconds, from a wide shot of the dome to a medium close-up. She turned from the telescope, folded her arms and smiled as the stars filled in.
A camera that follows the brief
The same observatory prompt we ran on Veo 3.1 gave a 4-second 16:9 shot down a raised walkway toward the dome. The camera moved forward as asked, and the brass telescope swung into the opening.
Compare tiers before you commit
We sent the same two-sentence paper boat prompt to Veo 3.1 and to Fast. Veo 3.1 filmed from water level with reeds in front; Fast centred the boat on the sun's reflection with ripples spreading round it. Run a few briefs on both before choosing a tier for a project.
Request parameters
| Parameter | Required | Description |
|---|---|---|
prompt | Yes | Required. Say what happens next, with the action, the camera and the sound. at least 1 characters · at most 4000 characters |
video_url | Yes | The clip to carry on, 60 seconds at most. The new segment starts from its last frame, so finish on a clean one; the source is not billed. at least 1 characters |
last_image_url | No | Optional final frame for the new segment. at least 1 characters |
duration_seconds | No | How long the new segment runs: 4, 6 or 8 seconds (default 8). |
Pricing
Priced on the new segment only (4, 6 or 8 seconds), at the image-to-video rate; your source clip is free. A job that fails or is declined costs nothing.
| Specification | Price |
|---|---|
| $0.36 / request |
| $0.54 / request |
| $0.72 / request |
Use cases
Batches of ads and social posts
The price per clip is low enough to run a whole set of 9:16 variants in one sitting: ten 4-second clips cost $3.60, sound included.
The same character or product across several clips
Send 1 to 3 reference images and call them Image 1, Image 2 and Image 3 in the prompt. In our test the face and jacket from Image 1 carried into a new scene.
Storyboards that start and end on set frames
Image to video takes a first frame and an optional last frame, so each shot of a sequence can begin and end where you planned.
Scenes longer than 8 seconds
Continue a clip with video extend: its last frame opens a new 4 to 8 second segment, billed at the image to video price, and the source is not billed.
Prompt guide & pro tips
Refer to references by number
Write "the man from Image 1" and "the observatory from Image 2", in upload order. Say what each one does; the images set the look, the prompt sets the action.
Crop references to what you want
Use one subject per image where you can. Fast left out a second person in our reference image, but other models may bring everything in.
Write the camera and the sound
Name one move, such as "Slow push-in" or "Handheld medium shot", and add a line like "Sound: footsteps on gravel, a metallic knock". Put spoken words in quotes.
Iterate at 4 seconds, finish at 8
At $0.36 a 4-second clip is cheap enough to try several wordings. When one works, render it at 8 seconds, or send the final version to Veo 3.1. Reference clips are 8 seconds from the start, $0.72.
Introduction
Veo 3.1 Fast Video extend is a SpicyAPI feature, not Google's own extension: the last frame of your clip, up to 60 seconds long, opens a new 4, 6 or 8 second segment made with Veo 3.1 Fast image to video, and you receive one MP4 with both parts joined. Prompt and images are screened by Google before generating, and a request it turns down fails without a charge.
Other Veo 3.1 Fast modes
- Only have an idea in words? Text to video writes the scene from your prompt alone.
- Starting from a still? Image to video animates a first frame and can finish on a last one.
- Need the same person or product in several clips? Reference to video takes up to 3 images.
Prompt tips
- Write only the next beat; the last frame already shows who is where.
- Stop the source clip on a sharp frame, since a blurred one carries into the new segment.
- Add a closing frame when the segment must land on a planned picture.
API quick start
# Generate the idempotency key once; reuse it when retrying after a lost response.
export SPICY_IDEMPOTENCY_KEY="${SPICY_IDEMPOTENCY_KEY:-$(uuidgen)}"
curl -X POST https://api.spicyapi.ai/api/v1/jobs/createTask \
-H "Authorization: Bearer $SPICY_API_KEY" \
-H "Content-Type: application/json" \
-H "Idempotency-Key: $SPICY_IDEMPOTENCY_KEY" \
-d '{
"model": "google/veo-3.1-fast/video-extend",
"input": {
"duration_seconds": 8,
"prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
"video_url": "https://example.com/reference.mp4"
}
}'
# Copy data.taskId from the response into TASK_ID, then poll the status.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.spicyapi.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $SPICY_API_KEY"
See the API reference for authentication, the complete schema, polling, and error handling.