HappyHorse 1.1 Reference-to-Video

curl --request POST \
  --url https://api.evolink.ai/v1/videos/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "happyhorse-1.1-reference-to-video",
  "prompt": "A woman in a red qipao character1, the camera first frames the slim cut of the qipao from a side medium shot, then switches to a low-angle upward shot capturing details as she gracefully lifts her hand to open a folding fan character2, with tasseled earrings character3 swaying lightly as she turns her head.",
  "image_urls": [
    "https://cdn.example.com/girl.jpg",
    "https://cdn.example.com/folding-fan.jpg",
    "https://cdn.example.com/earrings.jpg"
  ],
  "quality": "720p",
  "aspect_ratio": "16:9",
  "duration": 5
}
'

{
  "created": 1761313744,
  "id": "task-unified-1761313744-h1r2vef0",
  "model": "happyhorse-1.1-reference-to-video",
  "object": "video.generation.task",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": true,
    "estimated_time": 2400,
    "video_duration": 5
  },
  "type": "video",
  "usage": {
    "billing_rule": "per_second",
    "credits_reserved": 607500,
    "user_group": "default"
  }
}

{
  "error": {
    "code": "invalid_request",
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or expired token",
    "type": "authentication_error"
  }
}

{
  "error": {
    "code": "insufficient_quota",
    "message": "Insufficient quota. Please top up your account.",
    "type": "insufficient_quota"
  }
}

{
  "error": {
    "code": "model_access_denied",
    "message": "Token does not have access to model: happyhorse-1.1-reference-to-video",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "Too many requests, please try again later",
    "type": "rate_limit_error"
  }
}

{
  "error": {
    "code": "internal_error",
    "message": "Internal server error",
    "type": "api_error"
  }
}

POST

videos

generations

curl --request POST \
  --url https://api.evolink.ai/v1/videos/generations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "happyhorse-1.1-reference-to-video",
  "prompt": "A woman in a red qipao character1, the camera first frames the slim cut of the qipao from a side medium shot, then switches to a low-angle upward shot capturing details as she gracefully lifts her hand to open a folding fan character2, with tasseled earrings character3 swaying lightly as she turns her head.",
  "image_urls": [
    "https://cdn.example.com/girl.jpg",
    "https://cdn.example.com/folding-fan.jpg",
    "https://cdn.example.com/earrings.jpg"
  ],
  "quality": "720p",
  "aspect_ratio": "16:9",
  "duration": 5
}
'

{
  "created": 1761313744,
  "id": "task-unified-1761313744-h1r2vef0",
  "model": "happyhorse-1.1-reference-to-video",
  "object": "video.generation.task",
  "progress": 0,
  "status": "pending",
  "task_info": {
    "can_cancel": true,
    "estimated_time": 2400,
    "video_duration": 5
  },
  "type": "video",
  "usage": {
    "billing_rule": "per_second",
    "credits_reserved": 607500,
    "user_group": "default"
  }
}

{
  "error": {
    "code": "invalid_request",
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or expired token",
    "type": "authentication_error"
  }
}

{
  "error": {
    "code": "insufficient_quota",
    "message": "Insufficient quota. Please top up your account.",
    "type": "insufficient_quota"
  }
}

{
  "error": {
    "code": "model_access_denied",
    "message": "Token does not have access to model: happyhorse-1.1-reference-to-video",
    "type": "invalid_request_error"
  }
}

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "Too many requests, please try again later",
    "type": "rate_limit_error"
  }
}

{
  "error": {
    "code": "internal_error",
    "message": "Internal server error",
    "type": "api_error"
  }
}

Authorizations

Authorization

string

header

required

##All endpoints require Bearer Token authentication##

Get API Key:

Visit the API Key Management Page to obtain your API Key

Add to request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

model

enum<string>

default:happyhorse-1.1-reference-to-video

required

Video generation model name

Available options:

happyhorse-1.1-reference-to-video

Example:

"happyhorse-1.1-reference-to-video"

prompt

string

required

Text prompt, required

Length limits:

Chinese: up to 2500 characters
Non-Chinese: up to 5000 characters
Excess content is automatically truncated

Character reference convention (important):

The prompt must explicitly use character1, character2, character3 ... keywords to reference images in image_urls in order
The 1st image corresponds to character1, the 2nd to character2, and so on
Missing explicit references may cause character confusion

Example:

"A woman in a red qipao character1, the camera first frames the slim cut of the qipao from a side medium shot, then switches to a low-angle upward shot capturing details as she gracefully lifts her hand to open a folding fan character2, with tasseled earrings character3 swaying lightly as she turns her head."

image_urls

string<uri>[]

required

Reference image URL array, required, 1 ~ 9 images

Image requirements:

Supported formats: JPEG, JPG, PNG, WEBP
Resolution: short edge ≥ 400 px; 720P or higher quality images are recommended (avoid extremely small, blurry, or heavily compressed images)
Recommended aspect ratio: short edge / long edge ≥ 0.4, with consistent proportions across images (close to the target video ratio)
File size: ≤ 10MB per image
Image URLs must be publicly accessible (HTTP or HTTPS); private OSS, intranet, or authenticated links are not supported

Order: Array order corresponds to character1, character2 ... references in the prompt

Required array length: 1 - 9 elements

Example:

[
  "https://cdn.example.com/girl.jpg",
  "https://cdn.example.com/folding-fan.jpg",
  "https://cdn.example.com/earrings.jpg"
]

quality

enum<string>

default:720p

Video resolution tier, defaults to 720p

Options:

720p: Standard clarity, this is the default
1080p: HD clarity

Billing note: Resolution tier directly affects billing

Available options:

720p,

1080p

Example:

"720p"

aspect_ratio

enum<string>

default:16:9

Video aspect ratio, defaults to 16:9

Options:

16:9 (landscape)
9:16 (portrait)
1:1 (square)
4:3
3:4
4:5
5:4
9:21
21:9

Available options:

16:9,

9:16,

1:1,

4:3,

3:4,

4:5,

5:4,

9:21,

21:9

Example:

"16:9"

duration

integer

default:5

Video duration (seconds), defaults to 5 seconds

Range:

Integer 3 ~ 15
Duration directly affects billing

Required range: 3 <= x <= 15

Example:

5

seed

integer

Random seed, default is random

Details:

Range: 1 ~ 2147483647
A fixed seed reduces parameter-induced variation when iterating on prompts and improves reproducibility

Required range: 1 <= x <= 2147483647

Example:

42

callback_url

string<uri>

HTTPS callback URL for task completion

Callback timing:

Triggered when the task is completed, failed, or cancelled
Sent after billing confirmation is complete

Security restrictions:

Only HTTPS protocol is supported
Callbacks to private IP addresses are prohibited (127.0.0.1, 10.x.x.x, 172.16-31.x.x, 192.168.x.x, etc.)
URL length must not exceed 2048 characters

Callback mechanism:

Timeout: 10 seconds
Up to 3 retries after failure (at 1/2/4 seconds after failure respectively)
Callback response body format is consistent with the task query endpoint response format
A 2xx status code is considered successful; other status codes trigger retries

Example:

"https://your-domain.com/webhooks/video-task-completed"

Response

Video generation task created successfully

created

integer

Task creation timestamp

Example:

1761313744

string

Task ID

Example:

"task-unified-1761313744-h1r2vef0"

model

string

Actual model name used

Example:

"happyhorse-1.1-reference-to-video"

object

enum<string>

Specific type of the task

Available options:

video.generation.task

progress

integer

Task progress percentage (0-100)

Required range: 0 <= x <= 100

Example:

0

status

enum<string>

Task status

Available options:

pending,

processing,

completed,

failed,

cancelled

Example:

"pending"

task_info

object

Video task details

Show child attributes

type

enum<string>

Output type of the task

Available options:

text,

image,

audio,

video

Example:

"video"

usage

object

Usage and billing information

Show child attributes

Image Series

Video Series

Audio Series

Text Series

Account Management

Task Management

File Management

HappyHorse 1.1 Reference-to-Video

Authorizations

Body

Response