> ## Documentation Index
> Fetch the complete documentation index at: https://docs.evolink.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# HappyHorse 1.1 Reference-to-Video

> - HappyHorse 1.1 reference-to-video, supports 1–9 reference images plus a text prompt
- **Character reference convention**: in `prompt`, use `character1`, `character2`, `character3` ... keywords to reference the images in `image_urls` array in order
- Asynchronous processing mode, use the returned task ID to [query status](/en/api-manual/task-management/get-task-detail)
- Generated video links are valid for 24 hours, please save them promptly



## OpenAPI

````yaml /en/api-manual/video-series/happyhorse1.1/happyhorse-1.1-reference-to-video.json POST /v1/videos/generations
openapi: 3.1.0
info:
  title: HappyHorse 1.1 Reference-to-Video API
  description: >-
    HappyHorse 1.1 reference-to-video API, generates video from 1–9 reference
    images and a text prompt
  license:
    name: MIT
  version: 1.0.0
servers:
  - url: https://api.evolink.ai
    description: Production
security:
  - bearerAuth: []
tags:
  - name: Video Generation
    description: AI video generation endpoints
paths:
  /v1/videos/generations:
    post:
      tags:
        - Video Generation
      summary: HappyHorse 1.1 Reference-to-Video
      description: >-
        - HappyHorse 1.1 reference-to-video, supports 1–9 reference images plus
        a text prompt

        - **Character reference convention**: in `prompt`, use `character1`,
        `character2`, `character3` ... keywords to reference the images in
        `image_urls` array in order

        - Asynchronous processing mode, use the returned task ID to [query
        status](/en/api-manual/task-management/get-task-detail)

        - Generated video links are valid for 24 hours, please save them
        promptly
      operationId: createHappyHorse11ReferenceToVideo
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/VideoGenerationRequest'
            examples:
              multi_character:
                summary: Multi-character reference-to-video
                value:
                  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
              single_reference:
                summary: Single-image reference-to-video
                value:
                  model: happyhorse-1.1-reference-to-video
                  prompt: >-
                    character1 runs through a forest, with sunlight filtering
                    through the leaves
                  image_urls:
                    - https://cdn.example.com/character.jpg
                  quality: 1080p
                  aspect_ratio: '9:16'
                  duration: 6
      responses:
        '200':
          description: Video generation task created successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/VideoGenerationResponse'
        '400':
          description: Invalid request parameters
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: invalid_request
                  message: Invalid request parameters
                  type: invalid_request_error
        '401':
          description: Unauthenticated, token invalid or expired
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: unauthorized
                  message: Invalid or expired token
                  type: authentication_error
        '402':
          description: Insufficient quota, top-up required
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: insufficient_quota
                  message: Insufficient quota. Please top up your account.
                  type: insufficient_quota
        '403':
          description: Access denied
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: model_access_denied
                  message: >-
                    Token does not have access to model:
                    happyhorse-1.1-reference-to-video
                  type: invalid_request_error
        '429':
          description: Rate limit exceeded
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: rate_limit_exceeded
                  message: Too many requests, please try again later
                  type: rate_limit_error
        '500':
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: internal_error
                  message: Internal server error
                  type: api_error
components:
  schemas:
    VideoGenerationRequest:
      type: object
      required:
        - model
        - prompt
        - image_urls
      properties:
        model:
          type: string
          description: Video generation model name
          enum:
            - happyhorse-1.1-reference-to-video
          default: happyhorse-1.1-reference-to-video
          example: happyhorse-1.1-reference-to-video
        prompt:
          type: string
          description: >-
            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:
          type: array
          description: >-
            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
          items:
            type: string
            format: uri
          minItems: 1
          maxItems: 9
          example:
            - https://cdn.example.com/girl.jpg
            - https://cdn.example.com/folding-fan.jpg
            - https://cdn.example.com/earrings.jpg
        quality:
          type: string
          description: |-
            Video resolution tier, defaults to `720p`

            **Options:**
            - `720p`: Standard clarity, this is the default
            - `1080p`: HD clarity

            **Billing note:** Resolution tier directly affects billing
          enum:
            - 720p
            - 1080p
          default: 720p
          example: 720p
        aspect_ratio:
          type: string
          description: |-
            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`
          enum:
            - '16:9'
            - '9:16'
            - '1:1'
            - '4:3'
            - '3:4'
            - '4:5'
            - '5:4'
            - '9:21'
            - '21:9'
          default: '16:9'
          example: '16:9'
        duration:
          type: integer
          description: |-
            Video duration (seconds), defaults to `5` seconds

            **Range:**
            - Integer `3` ~ `15`
            - Duration directly affects billing
          default: 5
          minimum: 3
          maximum: 15
          example: 5
        seed:
          type: integer
          description: >-
            Random seed for deterministic outputs. Default is random; passing
            `0` (or omitting) is treated as unset.


            **Details:**

            - Range: `0` ~ `2147483647` (0 is treated as unset)

            - A fixed seed reduces parameter-induced variation when iterating on
            prompts and improves reproducibility
          minimum: 0
          maximum: 2147483647
          example: 42
        callback_url:
          type: string
          description: >-
            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
          format: uri
          example: https://your-domain.com/webhooks/video-task-completed
    VideoGenerationResponse:
      type: object
      properties:
        created:
          type: integer
          description: Task creation timestamp
          example: 1761313744
        id:
          type: string
          description: Task ID
          example: task-unified-1745726400000000000-aBcDeFgH-happyhorse-1.1-reference-to-video
        model:
          type: string
          description: Actual model name used
          example: happyhorse-1.1-reference-to-video
        object:
          type: string
          enum:
            - video.generation.task
          description: Specific type of the task
        progress:
          type: integer
          description: Task progress percentage (0-100)
          minimum: 0
          maximum: 100
          example: 0
        status:
          type: string
          description: Task status
          enum:
            - pending
            - processing
            - completed
            - failed
          example: pending
        task_info:
          $ref: '#/components/schemas/VideoTaskInfo'
          description: Video task details
        type:
          type: string
          enum:
            - text
            - image
            - audio
            - video
          description: Output type of the task
          example: video
        usage:
          $ref: '#/components/schemas/VideoUsage'
          description: Usage and billing information
    ErrorResponse:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
              description: Error code identifier
            message:
              type: string
              description: Error description message
            type:
              type: string
              description: Error type
    VideoTaskInfo:
      type: object
      properties:
        can_cancel:
          type: boolean
          description: Whether the task can be cancelled
          example: true
        estimated_time:
          type: integer
          description: Estimated completion time (seconds)
          minimum: 0
          example: 120
        video_duration:
          type: integer
          description: Video duration (seconds)
          example: 5
    VideoUsage:
      type: object
      description: Usage and billing information
      properties:
        billing_rule:
          type: string
          description: Billing rule
          enum:
            - per_call
            - per_token
            - per_second
          example: per_second
        credits_reserved:
          type: number
          description: Estimated credits consumed
          minimum: 0
          example: 60.75
        user_group:
          type: string
          description: User group category
          example: default
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        **All endpoints require Bearer Token authentication**


        **Get API Key:**


        Visit the [API Key Management Page](https://evolink.ai/dashboard/keys)
        to obtain your API Key


        **Add to request header:**

        ```

        Authorization: Bearer YOUR_API_KEY

        ```

````




# Query Task Status

> Query the status, progress, and result information of asynchronous tasks by task ID


## OpenAPI

````yaml en/api-manual/task-management/get-task-detail.json get /v1/tasks/{task_id}
openapi: 3.1.0
info:
  title: Get Task Details API
  description: >-
    Query the status, progress, and result information of asynchronous tasks by
    task ID
  license:
    name: MIT
  version: 1.0.0
servers:
  - url: https://api.evolink.ai
    description: Production environment
security:
  - bearerAuth: []
tags:
  - name: Task Management
    description: Asynchronous task management related APIs
paths:
  /v1/tasks/{task_id}:
    get:
      tags:
        - Task Management
      summary: Query Task Status
      description: >-
        Query the status, progress, and result information of asynchronous tasks
        by task ID
      operationId: getTaskDetail
      parameters:
        - name: task_id
          in: path
          required: true
          schema:
            type: string
          description: >-
            Task ID, ignore {} when querying, append the id from the async task
            response body at the end of the path
          example: task-unified-1745726400000000000-aBcDeFgH-happyhorse-1.1-reference-to-video
      responses:
        '200':
          description: Task status details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TaskDetailResponse'
        '400':
          description: Request parameter error, format error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: invalid_task_id
                  message: Invalid task ID format, must start with 'task-unified-'
                  type: invalid_request_error
                  param: task_id
        '401':
          description: Unauthenticated, token invalid or expired
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: unauthorized
                  message: Authentication required
                  type: authentication_error
        '402':
          description: Insufficient quota, recharge required
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: quota_exceeded
                  message: Insufficient quota. Please top up your account.
                  type: insufficient_quota
        '403':
          description: No permission to access
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: permission_denied
                  message: You don't have permission to access this task
                  type: invalid_request_error
        '404':
          description: Resource does not exist
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: task_not_found
                  message: The requested task could not be found
                  type: invalid_request_error
        '429':
          description: Request rate limit exceeded
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: rate_limit_exceeded
                  message: Rate limit exceeded
                  type: evo_api_error
        '500':
          description: Internal server error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
              example:
                error:
                  code: internal_error
                  message: Failed to retrieve task status
                  type: api_error
components:
  schemas:
    TaskDetailResponse:
      type: object
      properties:
        created:
          type: integer
          description: Task creation timestamp
          example: 1745726400
        id:
          type: string
          description: Task ID
          example: task-unified-1745726400000000000-aBcDeFgH-happyhorse-1.1-reference-to-video
        model:
          type: string
          description: Model used
          example: happyhorse-1.1-reference-to-video
        object:
          type: string
          description: Task type
          enum:
            - image.generation.task
            - video.generation.task
            - audio.generation.task
          example: video.generation.task
        progress:
          type: integer
          minimum: 0
          maximum: 100
          description: Task progress percentage
          example: 100
        results:
          type: array
          items:
            type: string
            format: uri
          description: Task result list (provided when completed). Video URLs are valid for 24 hours.
          example:
            - https://dashscope-result.oss-cn-beijing.aliyuncs.com/xxx.mp4?Expires=xxx
        status:
          type: string
          description: Task status
          enum:
            - pending
            - processing
            - completed
            - failed
          example: completed
        error:
          type: object
          nullable: true
          description: >-
            Error information when the task fails (only present when status is
            "failed"). Note: error.code here is a string-type business error
            code, different from HTTP status codes. See the Error Codes
            Reference for the complete list.
          properties:
            code:
              type: string
              description: Business error code (string type)
              example: content_policy_violation
            message:
              type: string
              description: User-friendly error description with troubleshooting tips
              example: |-
                Content policy violation.
                Your request was blocked by safety filters.
            type:
              type: string
              description: Error type identifier, always "task_error"
              example: task_error
        task_info:
          type: object
          description: Task detailed information
          properties:
            can_cancel:
              type: boolean
              description: Whether the task can be cancelled
              example: false
        type:
          type: string
          description: Task type
          enum:
            - image
            - video
            - audio
            - text
          example: video
    ErrorResponse:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
              description: Error code (string type)
              example: invalid_task_id
            message:
              type: string
              description: Error description message
              example: Invalid task ID format
            type:
              type: string
              description: Error type
              example: invalid_request_error
            param:
              type: string
              description: Related parameter name
              example: task_id
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        **All APIs require Bearer Token authentication**


        **Get API Key:**


        Visit [API Key Management Page](https://evolink.ai/dashboard/keys) to
        get your API Key


        **Add to request header:**

        ```

        Authorization: Bearer YOUR_API_KEY

        ```

````