> ## Documentation Index > Fetch the complete documentation index at: https://docs.vidgo.ai/llms.txt > Use this file to discover all available pages before exploring further. # Upload and Extend Audio > Extend audio tracks while preserving the original style 1. After submission, a `task_id` will be returned. If you provided a `callback_url`, when the task status becomes `finished` or `failed`, a POST request will be sent to the `callback_url`. 2. Regardless of whether `callback_url` is provided, you can retrieve the response result through the unified [Query Music Detail](/api-manual/music-series/query-music-detail) endpoint. ## Usage Guide * This endpoint extends uploaded audio files while preserving the original style * Upload an existing audio track and specify where to continue from * The AI generates additional content that seamlessly blends with the original * Uploaded audio files must not exceed 8 minutes in length (**Note**: For V4\_5ALL model, max 1 minute) ## Parameter Details * When `default_param_flag: true` (Custom Parameters Mode): * Full control over style, title, and other parameters * If `instrumental: true`: only `style`, `title`, and `upload_url` are required * If `instrumental: false`: `style`, `title`, `prompt` (used as exact lyrics), and `upload_url` are required * Character limits vary by model: * **V4**: `prompt` 3000 characters, `style` 200 characters, `title` 80 characters * **V4\_5 & V4\_5PLUS**: `prompt` 5000 characters, `style` 1000 characters, `title` 100 characters * **V4\_5ALL**: `prompt` 5000 characters, `style` 1000 characters, `title` 80 characters * **V5**: `prompt` 5000 characters, `style` 1000 characters, `title` 100 characters * When `default_param_flag: false`: * Only `upload_url` is required. If `instrumental: false`, lyrics will be automatically generated ## Developer Notes * Recommendation: Use `default_param_flag: false` for quick extensions that maintain the original style * The `continue_at` parameter determines where the extension begins - set it to the point where you want new content to start ## Optional parameters * `prompt` (string): Description or lyrics for the extended audio. Required when `default_param_flag` is `true` and `instrumental` is `false`. The prompt will be used strictly as lyrics. When `default_param_flag` is `false`, lyrics will be automatically generated based on the prompt. * `style` (string): Music style specification. Required when `default_param_flag` is `true`. * `title` (string): Track title for the extended audio. Character limits vary by model (V4: 80, V4\_5 & V4\_5PLUS & V5: 100, V4\_5ALL: 80). * `negative_tags` (string): Music styles to exclude from generation. * `vocal_gender` (string): Vocal gender preference. Use `m` for male, `f` for female. Note: This parameter can only increase the probability but cannot guarantee the specified gender. * `style_weight` (number): Strength of adherence to style. Range 0-1, up to 2 decimals. * `weirdness_constraint` (number): Controls creative deviation. Range 0-1, up to 2 decimals. * `audio_weight` (number): Balance weight for audio features. Range 0-1, up to 2 decimals. * `persona_id` (string): Persona ID to apply to the generated music. How to generate persona\_id, visit [generate-persona](/api-manual/music-series/generate-persona). ## OpenAPI ````yaml /api-manual/music-series/upload-and-extend-audio.json POST /api/generate/submit openapi: 3.0.0 info: title: Vidgo API - Upload and Extend Audio API description: Extend audio tracks while preserving the original style version: 1.0.0 servers: - url: https://api.vidgo.ai description: Production server security: - BearerAuth: [] paths: /api/generate/submit: post: tags: - Music Generation summary: Submit Upload and Extend Audio Task description: Upload an audio file and extend it while preserving the original style operationId: submitUploadExtendTask requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SubmitRequest' examples: default-params: summary: Default Parameters - Simple Extension value: model: upload-and-extend-audio callback_url: https://your-domain.com/callback input: upload_url: https://storage.example.com/audio.mp3 default_param_flag: true instrumental: true continue_at: 60 mv: V5 custom-params: summary: Custom Parameters - Full Control value: model: upload-and-extend-audio callback_url: https://your-domain.com/callback input: upload_url: https://storage.example.com/audio.mp3 default_param_flag: false instrumental: false prompt: Extend the music with more relaxing notes style: Classical title: Peaceful Piano Extended continue_at: 60 mv: V4_5PLUS negative_tags: Heavy Metal, Fast Drums vocal_gender: f style_weight: 0.65 instrumental-extension: summary: Instrumental Track Extension value: model: upload-and-extend-audio callback_url: https://your-domain.com/callback input: upload_url: https://storage.example.com/instrumental.mp3 default_param_flag: false instrumental: true style: Cinematic, Orchestral title: Epic Journey Extended continue_at: 90 mv: V5 style_weight: 0.7 weirdness_constraint: 0.3 responses: '200': description: Task submitted successfully content: application/json: schema: $ref: '#/components/schemas/SubmitResponse' components: schemas: SubmitRequest: type: object required: - model - input properties: model: type: string description: |- API model identifier. Must be `upload-and-extend-audio` for this endpoint. enum: - upload-and-extend-audio example: upload-and-extend-audio callback_url: type: string format: uri description: Webhook callback URL for result notifications example: https://your-domain.com/callback input: type: object required: - upload_url - default_param_flag - instrumental - continue_at - mv description: Input parameters for audio extension properties: upload_url: type: string format: uri description: >- The URL for uploading audio files, required regardless of whether `default_param_flag` is true or false. Ensure the uploaded audio does not exceed 8 minutes in length. **Note**: For the V4_5ALL model, the uploaded audio must not exceed 1 minute in length. example: https://storage.example.com/audio.mp3 default_param_flag: type: boolean description: >- Enable or disable custom parameter mode. - When `true`: Enables custom mode with full control over style, title, and other parameters. - When `false`: Only `upload_url` is required. example: true instrumental: type: boolean description: >- Determines whether the audio is instrumental (without lyrics). - In custom parameter mode (`default_param_flag: true`): - If `true`: only `style`, `title`, and `upload_url` are required. - If `false`: `style`, `title`, `prompt` (prompt will be used as exact lyrics), and `upload_url` are required. - In non-custom parameter mode (`default_param_flag: false`): does not affect required fields (only `upload_url` needed). If `false`, lyrics will be automatically generated. example: true continue_at: type: number description: >- The timestamp (in seconds) from which to start extending the audio. This defines where the original audio ends and the AI-generated extension begins. example: 60 mv: type: string description: >- AI model version for audio extension. - **V5**: Superior musical expression, faster generation. - **V4_5PLUS**: V4_5PLUS delivers richer sound, new ways to create, max 8 min. - **V4_5**: V4_5 enables smarter prompts, faster generations, max 8 min. - **V4_5ALL**: V4_5ALL enables smarter prompts, faster generations, max 8 min. - **V4**: V4 improves vocal quality, max 4 min. enum: - V4 - V4_5 - V4_5ALL - V4_5PLUS - V5 example: V5 prompt: type: string description: >- Description or lyrics for the extended audio. Required when `default_param_flag` is `true` and `instrumental` is `false`. The prompt will be used strictly as lyrics. When `default_param_flag` is `false`, lyrics will be automatically generated based on the prompt. Character limits by model: - **V4**: Maximum 3000 characters - **V4_5 & V4_5PLUS**: Maximum 5000 characters - **V4_5ALL**: Maximum 5000 characters - **V5**: Maximum 5000 characters maxLength: 5000 example: Extend the music with more relaxing notes style: type: string description: >- Music style specification defining genre, mood, or artistic direction. Required when `default_param_flag` is `true`. Character limits by model: - **V4**: Maximum 200 characters - **V4_5 & V4_5PLUS**: Maximum 1000 characters - **V4_5ALL**: Maximum 1000 characters - **V5**: Maximum 1000 characters maxLength: 1000 example: Classical title: type: string description: |- Track title displayed in player and used for file naming. Character limits by model: - **V4**: Maximum 80 characters - **V4_5 & V4_5PLUS**: Maximum 100 characters - **V4_5ALL**: Maximum 80 characters - **V5**: Maximum 100 characters maxLength: 100 example: Peaceful Piano Extended negative_tags: type: string description: >- Music styles or characteristics to exclude from generation. Specify unwanted genres, moods, or instruments to avoid in the output. example: Heavy Metal, Fast Drums vocal_gender: type: string description: >- Preferred vocal gender for the generated music. - `m`: Male vocals - `f`: Female vocals Only effective when `instrumental` is `false`. **Note**: This parameter increases the probability but cannot guarantee the specified gender. enum: - m - f example: f style_weight: type: number description: >- Controls how strongly the specified style influences the generation. Range: 0-1, up to 2 decimals. Higher values result in stronger adherence to the specified style. minimum: 0 maximum: 1 example: 0.65 weirdness_constraint: type: number description: >- Controls the level of experimental creativity and unconventional elements. Range: 0-1, up to 2 decimals. - Lower values: More conventional music - Higher values: More experimental and unique outputs minimum: 0 maximum: 1 example: 0.65 audio_weight: type: number description: >- Balances audio characteristics against other generation factors. Range: 0-1, up to 2 decimals. Adjusts the emphasis on audio quality and sonic features in the final output. minimum: 0 maximum: 1 example: 0.65 persona_id: type: string description: >- Persona ID to apply to the generated music. Use this to apply a specific persona style to your music generation. How to generate persona_id, visit [generate-persona](/api-manual/music-series/generate-persona). example: persona_123 SubmitResponse: type: object required: - code - data properties: code: type: integer example: 200 description: HTTP status code data: type: object required: - task_id - status - created_time properties: task_id: type: string example: task-unified-1757165031-uyujaw3d description: Unique task identifier for status tracking status: type: string enum: - not_started example: not_started description: Initial task status created_time: type: string format: date-time example: '2025-11-12T10:30:00' description: ISO 8601 timestamp when the task was created securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: API Key description: >- All API endpoints require Bearer Token authentication Get your API Key: Visit the [API Key Management Page](https://vidgo.ai/apis/dashboard/api-key) to get your API Key Add it to the request header: ``` Authorization: Bearer VIDGO_API_KEY ``` ````