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

# Seedance 1.5 Pro I2V

> [Core Function] Seedance 1.5 Pro I2V is a joint audio-video image-to-video model. [Strengths] It accurately follows complex instructions to animate a single image with synchronized audio. [Best For] Recommended for: standard image animation tasks where 2.0's multi-reference capabilities are not required. [Limitations] Lacks the robust multi-shot and multi-image reference features of 2.0. [Routing] Use this if the user specifically requests the 1.5 architecture, otherwise default to 2.0.



## OpenAPI

````yaml /media-model-api/bytedance/bytedance-i2v.json post /bytedance/seedance-1.5-pro-i2v
openapi: 3.1.0
info:
  description: The image-to-video models API from ByteDance.
  version: 1.0.0
  contact:
    name: Modellix Support
    email: support@modellix.ai
  title: ByteDance Image-to-Video Models API
servers:
  - url: https://api.modellix.ai/api/v1
    description: The image-to-video models API from ByteDance.
security:
  - bearerAuth: []
paths:
  /bytedance/seedance-1.5-pro-i2v:
    post:
      summary: Seedance 1.5 Pro I2V
      description: >-
        [Core Function] Seedance 1.5 Pro I2V is a joint audio-video
        image-to-video model. [Strengths] It accurately follows complex
        instructions to animate a single image with synchronized audio. [Best
        For] Recommended for: standard image animation tasks where 2.0's
        multi-reference capabilities are not required. [Limitations] Lacks the
        robust multi-shot and multi-image reference features of 2.0. [Routing]
        Use this if the user specifically requests the 1.5 architecture,
        otherwise default to 2.0.
      operationId: seedance15ProI2vAsync
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Seedance15ProI2vRequest'
            examples:
              basic:
                summary: Basic first frame
                value:
                  first_frame_image: https://example.com/image.jpg
                  prompt: The person smiles and waves
              with_audio:
                summary: With audio generation
                value:
                  first_frame_image: https://example.com/first.jpg
                  last_frame_image: https://example.com/last.jpg
                  prompt: '"Hello world!" said happily'
                  generate_audio: true
                  duration: -1
      responses:
        '200':
          description: Task submitted successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AsyncTaskResponse'
components:
  schemas:
    Seedance15ProI2vRequest:
      type: object
      description: At least one of first_frame_image or last_frame_image must be provided.
      properties:
        prompt:
          type: string
          minLength: 1
          maxLength: 10000
          description: >-
            Description of the desired output. Maximum 10000 characters.
            Recommended prompt length: under 1000 words. Lengthy text will lead
            to scattered information, and the model may ignore details and only
            focus on key points, resulting in missing elements in the generated
            video.
        first_frame_image:
          type: string
          minLength: 1
          description: URL or Base64 data for the first frame image.
          example: https://example.com/first.jpg
        last_frame_image:
          type: string
          minLength: 1
          description: URL or Base64 data for the last frame image.
          example: https://example.com/last.jpg
        ratio:
          type: string
          enum:
            - '16:9'
            - '4:3'
            - '1:1'
            - '3:4'
            - '9:16'
            - '21:9'
            - adaptive
          default: adaptive
          description: Aspect ratio of the generated video.
        resolution:
          type: string
          enum:
            - 480p
            - 720p
            - 1080p
          default: 720p
          description: Output resolution of the video.
        duration:
          type: integer
          description: Video duration in seconds (4-12 seconds).
          default: 5
          enum:
            - 4
            - 5
            - 6
            - 7
            - 8
            - 9
            - 10
            - 11
            - 12
        seed:
          type: integer
          default: -1
          minimum: -1
          maximum: 2147483647
          description: Random seed for reproducible generation. Use -1 for random.
        camera_fixed:
          type: boolean
          default: false
          description: Whether to keep the camera fixed during generation.
        generate_audio:
          type: boolean
          description: Whether to generate audio. 1.5 Pro exclusive feature.
          default: true
        service_tier:
          type: string
          enum:
            - default
            - flex
          default: default
          description: Service tier for generation (e.g., default or flex).
        execution_expires_after:
          type: integer
          default: 172800
          minimum: 3600
          maximum: 259200
          description: Task expiration time in seconds.
        return_last_frame:
          type: boolean
          default: false
          description: Whether to return the last frame of the generated video.
    AsyncTaskResponse:
      type: object
      required:
        - code
        - message
        - data
      properties:
        code:
          type: integer
          description: Response code, 0 indicates success
          example: 0
        message:
          type: string
          description: Response message
          example: success
        data:
          type: object
          required:
            - status
            - task_id
            - model_id
          properties:
            status:
              type: string
              enum:
                - pending
                - processing
              description: Task status
              example: pending
            task_id:
              type: string
              description: Unique task identifier
              example: task-abc123
            model_id:
              type: string
              description: Model ID
              example: model-123
            get_result:
              type: object
              description: API information to query the task result
              properties:
                method:
                  type: string
                  description: HTTP method
                  example: GET
                url:
                  type: string
                  description: Full URL to query the task result
                  example: https://api.modellix.ai/api/v1/tasks/task-abc123
          description: Detailed data about the submitted asynchronous task.
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'API Key authentication. Format: `Bearer YOUR_API_KEY`.'

````