> ## Documentation Index > Fetch the complete documentation index at: https://www.tella.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Add a sound effect to a clip > Adds a sound effect to a clip from an uploaded audio source. Call `create_source` first. ## OpenAPI ````yaml /openapi.json post /v1/videos/{id}/clips/{clipId}/sound-effects openapi: 3.0.3 info: description: >- The Tella Public API allows you to programmatically access your videos and playlists, including transcripts, chapters, and thumbnails. ## Authentication All requests require a Bearer token in the Authorization header: ``` Authorization: Bearer tella_pk_xxxxx... ``` API keys can be generated in your Tella workspace settings. ## Rate Limiting The API is rate-limited to 100 requests per minute per organization. Rate limit information is returned in response headers: - `X-RateLimit-Limit`: Maximum requests per window - `X-RateLimit-Remaining`: Remaining requests in current window - `X-RateLimit-Reset`: Unix timestamp when the window resets title: Tella Public API version: 1.0.0 servers: - description: Production url: https://api.tella.com security: [] tags: - description: Video operations name: Videos - description: Sections of a video name: Clips - description: Playlist operations name: Playlists - description: Sidebar groups for organizing playlists name: Playlist Groups - description: Tags for categorizing and filtering videos name: Tags - description: Webhook endpoint management name: Webhooks paths: /v1/videos/{id}/clips/{clipId}/sound-effects: post: tags: - Clips summary: Add a sound effect to a clip description: >- Adds a sound effect to a clip from an uploaded audio source. Call `create_source` first. operationId: addClipSoundEffect parameters: - description: Video identifier in: path name: id required: true schema: description: Video identifier example: vid_abc123def456 type: string - description: Clip identifier in: path name: clipId required: true schema: description: Clip identifier example: cl_xyz789ghi012 type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/AddClipSoundEffectRequest' required: true responses: '200': content: application/json: schema: $ref: '#/components/schemas/ClipSoundEffectResponse' description: OK '400': content: application/json: example: error: code: bad_request doc_url: https://tella.tv/docs/api-reference/errors#bad-request message: The request was malformed or contained invalid parameters. schema: $ref: '#/components/schemas/ErrorResponse' description: The request was malformed or contained invalid parameters. '401': content: application/json: example: error: code: unauthorized doc_url: https://tella.tv/docs/api-reference/errors#unauthorized message: Authentication is required. Provide a valid API key. schema: $ref: '#/components/schemas/ErrorResponse' description: Authentication is required. Provide a valid API key. '403': content: application/json: example: error: code: forbidden doc_url: https://tella.tv/docs/api-reference/errors#forbidden message: You don't have permission to access this resource. schema: $ref: '#/components/schemas/ErrorResponse' description: You don't have permission to access this resource. '404': content: application/json: example: error: code: not_found doc_url: https://tella.tv/docs/api-reference/errors#not-found message: The requested resource was not found. schema: $ref: '#/components/schemas/ErrorResponse' description: The requested resource was not found. '422': content: application/json: example: error: code: unprocessable_entity doc_url: >- https://tella.tv/docs/api-reference/errors#unprocessable-entity message: The request was well-formed but contained semantic errors. schema: $ref: '#/components/schemas/ErrorResponse' description: The request was well-formed but contained semantic errors. '429': content: application/json: example: error: code: rate_limit_exceeded doc_url: >- https://tella.tv/docs/api-reference/errors#rate-limit-exceeded message: You have exceeded the rate limit. Please slow down. schema: $ref: '#/components/schemas/ErrorResponse' description: You have exceeded the rate limit. Please slow down. '500': content: application/json: example: error: code: internal_server_error doc_url: >- https://tella.tv/docs/api-reference/errors#internal-server-error message: An unexpected error occurred on the server. schema: $ref: '#/components/schemas/ErrorResponse' description: An unexpected error occurred on the server. security: - BearerAuth: [] components: schemas: AddClipSoundEffectRequest: additionalProperties: false description: Add a sound effect to a clip from an uploaded audio source. properties: durationMs: example: 3000 exclusiveMinimum: true maximum: 9007199254740991 type: integer name: example: Whoosh type: string sourceId: description: >- Source ID for the audio, from `POST /v1/sources` (`kind: audio` with the audio's duration). Upload the audio file as-is — MP3, WAV, M4A, … — no need to wrap it in an MP4. example: su_abc123 type: string startTimeMs: description: >- Start time. Milliseconds on the clip playback timeline (with cuts applied) — the same timeline as the cut transcript. example: 1000 maximum: 9007199254740991 minimum: 0 type: integer volume: description: Playback volume (1 = original). Defaults to 1. example: 1 exclusiveMinimum: true minimum: 0 type: number required: - sourceId - startTimeMs - durationMs type: object ClipSoundEffectResponse: additionalProperties: false description: A sound effect on a clip properties: soundEffect: $ref: '#/components/schemas/ClipSoundEffect' required: - soundEffect type: object ErrorResponse: additionalProperties: false description: Standard error response format properties: error: additionalProperties: false description: Error details properties: code: description: Machine-readable error code enum: - bad_request - unauthorized - forbidden - not_found - unprocessable_entity - rate_limit_exceeded - internal_server_error example: not_found type: string doc_url: description: Link to documentation for this error example: https://tella.tv/docs/api-reference/errors#not-found format: uri type: string message: description: Human-readable error message example: The requested resource was not found. type: string required: - code - message - doc_url type: object required: - error type: object ClipSoundEffect: additionalProperties: false description: A sound effect on a clip. properties: durationMs: example: 3000 minimum: 0 type: number id: description: Sound effect ID example: ly_abc123 type: string name: example: Whoosh nullable: true type: string sourceId: example: su_abc123 nullable: true type: string startTimeMs: description: >- Start time. Milliseconds on the clip playback timeline (with cuts applied) — the same timeline as the cut transcript. example: 1000 minimum: 0 type: number volume: description: Playback volume (1 = original). example: 1 type: number required: - id - startTimeMs - durationMs - volume type: object securitySchemes: BearerAuth: description: API key obtained from your Tella account settings scheme: bearer type: http ````