⌘K

HappyHorse 1.0 - First Frame Image to Video

happyhorse_1.0_i2v

HappyHorse 1.0 First Frame Image to Video generates smooth videos from a first-frame image and an optional text prompt.

API Notes

happyhorse_1.0_i2v generates videos at 24fps in MP4 format and supports 720P and 1080P resolution for 3 to 15 seconds

happyhorse_1.0_i2v does not support ratio; the output aspect ratio follows the first frame image

Authentication

authorization string required

All APIs require authentication via Bearer Token.

Get API Key:

Visit API Key Management Page to get your API Key.

Usage:

Add to request header:

Authorization: Bearer YOUR_API_KEY

Parameters

model string required

Model ID to use for the request

Value: happyhorse_1.0_i2v

input object required

Input parameters for the generation request

prompt string

Text prompt used to describe the generated video content. Supports Chinese and English. Chinese prompts support up to 2500 characters, and non-Chinese prompts support up to 5000 characters. Content exceeding the limit is automatically truncated

Example: The horse starts running forward through the field

media array required

Input media array. Provide exactly one first-frame image

type string required

Media type

Value: first_frame

url string required

First-frame image URL or Base64-encoded image data

Image requirements:
Supported formats: JPEG, JPG, PNG, WEBP
Width and height: at least 300 pixels
Aspect ratio: from 1:2.5 to 2.5:1
File size: maximum 20MB

Input formats:
Publicly accessible HTTP or HTTPS URL
Base64 format: data:{MIME_type};base64,{base64_data}
MIME types: JPEG/JPG image/jpeg, PNG image/png, WEBP image/webp

Example: https://example.com/first-frame.jpg

parameters object

Generation parameters

resolution string

Video resolution. This parameter affects billing because different resolution tiers have different unit prices

Options: 720P, 1080P

Default: 1080P

duration integer

Video duration in seconds. Billing is based on successfully generated output video seconds, so this parameter affects cost

Range: 3 - 15

Default: 5

watermark boolean

Whether to add a watermark to the lower-right corner of the generated video. The fixed watermark text is “Happy Horse”

Options: true, false

Default: true

seed integer

Random seed. If not specified, the system automatically generates a random seed. To improve reproducibility, use the same seed value for repeated calls

Range: 0 - 2147483647

Polling

Since result generation takes time, you need to poll the task status after creating the task.

The initial response only returns information such as the task ID and initial status. The final result must be obtained by polling the task status endpoint using the task ID.

See the examples on the right for polling requests and responses.

Response Format

error object

Error information, only present when status is failed

code string

Error code

message string

Detailed error message

output array

Generation results, only present when status is completed

content array

List of generated resource content

type string

Resource type

Value: image｜video

url string

Processed resource URL

jobId string

Remote task ID

usage object

Usage statistics, only present when status is completed

cost string

Total cost in USD

discount number

Discount amount

metadata object

Metadata information