Wan 2.7 Image-to-Video

Validation

mkdir -p output/aliyun-wan-i2v
python -m py_compile skills/ai/video/aliyun-wan-i2v/scripts/generate_i2v.py && echo "py_compile_ok" > output/aliyun-wan-i2v/validate.txt

Pass criteria: command exits 0 and output/aliyun-wan-i2v/validate.txt is generated.

Output And Evidence

Save task IDs, polling responses, and final video URLs to output/aliyun-wan-i2v/.
Keep at least one end-to-end run log for troubleshooting.

Prerequisites

Install SDK (recommended in a venv):

python3 -m venv .venv
. .venv/bin/activate
python -m pip install dashscope

Set DASHSCOPE_API_KEY in your environment, or add dashscope_api_key to ~/.alibabacloud/credentials.

Critical model names

wan2.7-i2v — supports first-frame, first+last frame, video continuation, and audio-driven generation

Capabilities

Capability	Description	Required media types
First-frame video	Generate video from a single image	`first_frame`
First+last frame	Interpolate video between two images	`first_frame` + `last_frame`
Video continuation	Extend an existing video clip	`first_clip`
Audio-driven	Drive video with audio (lip-sync, rhythm)	`first_frame` + `driving_audio`

API endpoint (async only)

POST https://dashscope.aliyuncs.com/api/v1/services/aigc/video-generation/video-synthesis

Required headers:

Authorization: Bearer $DASHSCOPE_API_KEY
Content-Type: application/json
X-DashScope-Async: enable

Singapore endpoint: replace dashscope.aliyuncs.com with dashscope-intl.aliyuncs.com.

Normalized interface

Request

prompt (string, optional) — up to 5000 characters, describes desired video content
negative_prompt (string, optional) — up to 500 characters
media (array, required) — media objects with type and url fields:
- type: first_frame | last_frame | driving_audio | first_clip
- url: public URL (HTTP/HTTPS) or OSS temporary URL
resolution (string, optional) — 720P or 1080P (default: 1080P)
duration (integer, optional) — video length in seconds, range [2, 15] (default: 5)
prompt_extend (boolean, optional) — AI prompt rewriting (default: true)
watermark (boolean, optional) — add "AI generated" watermark (default: false)
seed (integer, optional) — range [0, 2147483647]

Media input limits

Images (first_frame, last_frame):

Formats: JPEG, JPG, PNG (no transparency), BMP, WEBP
Resolution: [240, 8000] pixels per side
Aspect ratio: 1:8 to 8:1
Max size: 20MB

Audio (driving_audio):

Formats: wav, mp3
Duration: 2-30s
Max size: 15MB
Auto-truncated to duration value if longer

Video (first_clip):

Formats: mp4, mov
Duration: 2-10s
Resolution: [240, 4096] pixels per side
Aspect ratio: 1:8 to 8:1
Max size: 100MB

Response (task creation)

output.task_id (string) — use for polling, valid 24 hours
output.task_status (string) — PENDING | RUNNING | SUCCEEDED | FAILED | CANCELED
request_id (string)

Response (task result)

output.video_url (string) — generated video URL
output.orig_prompt (string) — original prompt
output.actual_prompt (string) — rewritten prompt (if prompt_extend enabled)
usage.video_count (integer)
usage.video_duration (integer) — duration in seconds

Quick start (Python + HTTP)

import os
import json
import time
import requests

API_KEY = os.getenv("DASHSCOPE_API_KEY")
BASE_URL = "https://dashscope.aliyuncs.com/api/v1"

def create_i2v_task(req: dict) -> str:
    """Create an image-to-video task and return task_id."""
    payload = {
        "model": "wan2.7-i2v",
        "input": {
            "prompt": req.get("prompt", ""),
            "media": req["media"],
        },
        "parameters": {
            "resolution": req.get("resolution", "1080P"),
            "duration": req.get("duration", 5),
            "prompt_extend": req.get("prompt_extend", True),
            "watermark": req.get("watermark", False),
        },
    }
    if req.get("negative_prompt"):
        payload["input"]["negative_prompt"] = req["negative_prompt"]
    if req.get("seed") is not None:
        payload["parameters"]["seed"] = req["seed"]

    resp = requests.post(
        f"{BASE_URL}/services/aigc/video-generation/video-synthesis",
        headers={
            "Authorization": f"Bearer {API_KEY}",
            "Content-Type": "application/json",
            "X-DashScope-Async": "enable",
        },
        json=payload,
    )
    resp.raise_for_status()
    data = resp.json()
    return data["output"]["task_id"]


def poll_task(task_id: str, interval: int = 15) -> dict:
    """Poll until task completes. Returns final response."""
    while True:
        resp = requests.get(
            f"{BASE_URL}/tasks/{task_id}",
            headers={"Authorization": f"Bearer {API_KEY}"},
        )
        resp.raise_for_status()
        data = resp.json()
        status = data["output"]["task_status"]
        if status in ("SUCCEEDED", "FAILED", "CANCELED"):
            return data
        time.sleep(interval)

Media combination examples

# First-frame only
media = [{"type": "first_frame", "url": "https://example.com/image.jpg"}]

# First + last frame interpolation
media = [
    {"type": "first_frame", "url": "https://example.com/start.jpg"},
    {"type": "last_frame", "url": "https://example.com/end.jpg"},
]

# Audio-driven from first frame
media = [
    {"type": "first_frame", "url": "https://example.com/face.jpg"},
    {"type": "driving_audio", "url": "https://example.com/speech.mp3"},
]

# Video continuation
media = [{"type": "first_clip", "url": "https://example.com/clip.mp4"}]

Error handling

Error	Likely cause	Action
401/403	Missing or invalid `DASHSCOPE_API_KEY`	Check env var or credentials file
400 `InvalidParameter`	Unsupported resolution, bad duration, missing media	Validate parameters
"does not support synchronous calls"	Missing `X-DashScope-Async: enable` header	Add required header
429	Rate limit or quota	Retry with backoff

Output location

Default output: output/aliyun-wan-i2v/videos/
Override base dir with OUTPUT_DIR.

Anti-patterns

Do not use model names other than wan2.7-i2v.
Do not call this API synchronously — async header is required.
Do not pass duplicate media types (e.g., two first_frame entries).
Video URLs expire after 24 hours; download and persist immediately.
Do not use this API for video editing — use aliyun-wan-videoedit instead.

Workflow

Confirm user intent: first-frame, first+last frame, video continuation, or audio-driven.
Prepare media array with correct types and valid URLs.
Create async task and poll for results.
Download and save generated video before URL expiration.

References

See references/api_reference.md for full HTTP API details.
See references/sources.md for source links.