Introduction
Wan 2.5 Video Extend continues a clip you already have. Send it as video_url and, if you like, a prompt for what happens next. The final frame of your clip becomes the opening frame of a new Wan 2.5 image-to-video shot of 5 or 10 seconds, and the two are joined into one MP4: your original first, then the continuation, with the repeated seam frame removed. The new segment also comes back as its own file, so you can keep extending or edit the pieces separately.
Key features
Continuity comes from the last frame. Wardrobe, set, light and where everyone stands carry over because the new segment literally starts on your final frame. Motion does not carry over the same way: the model sees one still, not the whole clip, so describe the movement you want to continue instead of assuming it will keep its speed or direction.
One file back, plus the new piece on its own. The joined MP4 keeps your clip’s frame rate and its framing, with no black bars. To line the seam up, the picture may be trimmed or adjusted by a few percent at the edges. If the model returns a noticeably different shape, the new segment is scaled to fill your frame and centered, cropping what spills over. It is encoded as H.264 MP4 with AAC sound. Sound from your source stays; sound for the new segment follows it; a silent side is padded with silence so picture and sound stay in step at the seam. The second asset in the output is the new segment alone, ready for another extend or for an editor.
Bring your own sound for the new part. Pass audio_url and the new segment is built against that track, so a spoken line or a beat lands where you expect. It shapes only the new segment: your original keeps the sound it had, and the two are joined as they are.
Everything else is Wan 2.5 image-to-video.
Request parameters
| Parameter | Required | Description |
|---|---|---|
audio_url | No | The voice or music track to use. |
duration_seconds | No | How long the clip runs. You pay per second. 5 · 10 · Default: 5 |
enable_prompt_expansion | No | Lets the model add detail to a short prompt. Default: false |
negative_prompt | No | Things you don't want to see. |
prompt | No | Describe what happens next: the action that follows, the camera move and the mood. |
resolution | No | Output size. Bigger sizes look sharper and cost more. 480p · 720p · 1080p · Default: 720p |
seed | No | Reuse the same number to get a repeatable result. ≥ 0 · ≤ 2147483647 |
video_url | Yes | The clip to work on. |
Pricing
Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.
| Option | Credits per second | ≈ USD |
|---|---|---|
| resolution 480p | 6.75 | $0.068 |
| resolution 720p | 13.5 | $0.14 |
| resolution 1080p | 20.25 | $0.20 |
Each task is rounded up to whole credits, so one run at the lowest tier costs 34 credits for a 5-second clip ($0.34).
For an exact number before you run, send the same body to POST /jobs/quote.
Use cases
Lengthen a shot that ended too early: a product turntable that stops before the label faces camera, or a walk that cuts before the subject reaches the door. Extend it by a few seconds and describe only the remaining motion.
Build a longer sequence step by step. Because every step starts from a single frame, watch each seam before stacking the next one.
Prompt guide & pro tips
Describe the next beat, not the whole scene. The frame already fixes who and where, so spend the prompt on the action that follows, the camera move and the sound. Repeat the camera language your clip ended on, such as a slow push in or a locked shot, so the seam reads as one take. The prompt is optional, but one clear action line gives steadier motion than none.
Trim before you extend. The last frame is the only picture the model sees, so a blurred, mid-cut or heavily compressed ending carries straight into the continuation. Cut your source on a clean, sharp frame first. Sources of up to 60 seconds are accepted as MP4, MOV or WebM.
Match the resolution to your source. resolution only sets how sharp the new segment is generated.
API quick start
Call the Wan 2.5 API in three steps
- Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
- Send the request. POST /jobs/createTask with model alibaba/wan-2.5/video-extend and an input object that follows the parameter table. The response returns a task ID straight away.
- Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.
# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
-H "Authorization: Bearer $POPNOW_API_KEY" \
-H "Content-Type: application/json" \
-H "Idempotency-Key: $IDEMPOTENCY_KEY" \
-d '{
"model": "alibaba/wan-2.5/video-extend",
"input": {
"video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4",
"resolution": "720p",
"duration_seconds": 5
}
}'
# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $POPNOW_API_KEY"Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.
Wan 2.5 API questions
How much does the Wan 2.5 API cost?
Wan 2.5 starts at 34 credits ($0.34) for a 5-second clip with Extend Video, its cheapest task. Prices by option: 480p 6.75 credits per second, 720p 13.5 credits per second, 1080p 20.25 credits per second. Credits are the same as on the website (1 credit = $0.01), new accounts get 30 free credits, and failed tasks are refunded.
What is the model name for Wan 2.5 in the API?
Put alibaba/wan-2.5/text-to-video for Create Video; alibaba/wan-2.5/image-to-video for Image to Video; alibaba/wan-2.5/video-extend for Extend Video in the model field of POST /jobs/createTask.
Does Wan 2.5 generate sound?
Yes. Sound is produced in the same pass as the picture, so the file comes back with audio already in place. Pass audio_url when the clip should follow a specific voice line or music cue.
How long can a Wan 2.5 clip be?
Exactly 5 or 10 seconds. duration_seconds accepts only those two values, so 7 is a validation error rather than a rounded request.
Which resolutions are available?
480p, 720p and 1080p, with 720p as the default. Resolution sets the per-second rate, so explore at 720p and rerender the keeper at 1080p.
Can I choose the aspect ratio?
On text-to-video, yes: 16:9, 9:16, 1:1, 4:3 or 3:4, with 4:3 and 3:4 needing 720p or higher. Image-to-video uses the proportions of the frame you send.
What are the limits of the Wan 2.5 API?
Clip length: 5–10 s; Resolutions: 480p · 720p · 1080p; Prompt length (characters): 1,500; Longest input clip: 60 s. Requests outside these limits are rejected before anything is charged.
Can I try Wan 2.5 without writing code?
Yes. The Playground runs Wan 2.5 on your PopNow credits, needs no API key, and shows the matching code for every run.
All Wan models
Wan 2.6 adds multi-shot clips and reference scenes; Wan 3.0 runs up to 30 seconds.
- Wan 3.0 APIUp to 30-second clips with synced audioFrom 34 credits for a 5-second clip
- Wan 3.0 Prime APIQuicker Wan 3.0 renders, up to 30 seconds with audioFrom 46 credits for a 5-second clip
- Wan 3.0 Pro Prime APIQuicker Wan 3.0 Pro with 2K and 4K outputFrom 176 credits for a 5-second clip
- Wan 3.0 Pro APIWan 3.0 at 1080p, 2K or 4K, up to 30 secondsFrom 108 credits for a 5-second clip
- Wan 2.7 Pro APILarge 4K canvases and nine-image compositesFrom 12 credits per image
- Wan 2.7 APIThinks through the composition, then draws up to four imagesFrom 5 credits per image
- Wan 2.6 Flash APIQuick multi-shot clips from a single imageFrom 17 credits for a 5-second clip
- Wan 2.6 APIMulti-shot sequences with sound at up to 1080pFrom 49 credits for a 5-second clip
- Wan 2.5 API1080p clips with sound that can follow your own audioFrom 34 credits for a 5-second clip
- Wan 2.2 Animate APIDrive a character photo with a reference videoFrom 7.95 credits per second
- Wan 2.2 LoRA APIWan 2.2 video with your LoRAs on either expert passFrom 18 credits for a 5-second clip
- Wan 2.2 APISimple five-second clips at 480p or 720pFrom 36 credits per run
- Wan 2.2 5B LoRA APILight 720p Wan 2.2 clips that load your own LoRAsFrom 18 credits per run
- Wan 2.2 Image LoRA APIWan 2.2 stills with up to nine LoRAs across three slotsFrom 5 credits per image
- Wan 2.1 LoRA APIWan 2.1 video and edits with your own LoRAs, camera moves includedFrom 36 credits per run
- Wan 2.1 Image LoRA APIPhotoreal Wan 2.1 stills and restyles with your LoRAsFrom 5 credits per image

