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POST
Video Fast Extend 1.1 — video extend

Authorizations

Authorization
string
header
required

Your API key from the developer console, sent as Authorization: Bearer sk_live_.... The x-api-key: sk_live_... header is accepted as an alternative.

Headers

Idempotency-Key
string

Optional key that makes the request safe to retry: any string up to 128 characters, unique per account, kept for 24 hours. The same key with the same body replays the first answer (Idempotent-Replayed: true) instead of creating a second task. See Idempotency.

Maximum string length: 128
Example:

"order-8812-attempt-1"

Body

application/json
video_url
string<uri>
required

Public HTTPS URL of the MP4 or MOV clip to continue, 360–2,000 px per side, at most 500 MB. The clip (after the optional window) must be 2–30 seconds long.

Example:

"https://assets.example.com/inputs/clip.mp4"

prompt
string
required

How the video continues after the clip.

Maximum string length: 2000
Example:

"the camera keeps panning right across the skyline"

duration
integer
required

Seconds to add after the clip. Clip plus added seconds may not exceed 30 seconds.

Required range: 3 <= x <= 30
Example:

5

resolution
enum<string>
required

Output resolution.

Available options:
480p,
720p,
1080p
Example:

"480p"

start_time
number

Start of the window of the clip to continue from, in seconds. Send start_time and end_time together, or neither.

Required range: x >= 0
Example:

0

end_time
number

End of the window, in seconds. Must be greater than start_time.

Example:

8

generate_audio
boolean
default:false

Generate synchronized audio together with the video.

prompt_expansion
enum<string>
default:advanced

How much the prompt is rewritten before generation: none keeps your text, basic polishes it, advanced expands it into a detailed shot description. The final text is returned as output.actual_prompt.

Available options:
none,
basic,
advanced
webhook_url
string<uri>

Public HTTPS URL that receives this task's events. Overrides your account's default webhook endpoint.

Example:

"https://hooks.example.com/fiveapi"

metadata
object

Your own JSON, up to 4,096 bytes when serialized. Returned unchanged on the task and in every webhook.

Example:

Response

The task was accepted and queued.

A generation task. error is always present (null unless the task failed); other empty members are omitted.

id
string
required

Task id, task_ followed by 26 characters.

Example:

"task_01J9X7Z0K7Q8W3F2P1N6M5V4R3"

object
string
required
Allowed value: "task"
model
string
required

The model id the task was created with.

Example:

"wan/v3.0-spark/image-to-video"

task
enum<string>
required

The task type, the last segment of the model id.

Available options:
text-to-video,
image-to-video,
reference-to-video,
video-extend
status
enum<string>
required

queued → processing → one of the terminal states completed, failed, cancelled.

Available options:
queued,
processing,
completed,
failed,
cancelled
input
object
required

The accepted request body, without webhook_url and metadata.

error
object | null
required

Why the task failed. null unless status is failed.

credits
object
required
created_at
string<date-time>
required

When the task was created.

output
object

The result. Present on completed tasks until expires_at.

queue
object

Present while the task is queued.

webhook_url
string<uri>

The webhook URL sent with the task.

metadata
object

The metadata sent with the task.

started_at
string<date-time>

When generation started.

completed_at
string<date-time>

When the task reached completed, failed or cancelled.

expires_at
string<date-time>

When the output is removed, 7 days after completion.