> ## Documentation Index > Fetch the complete documentation index at: https://docs.modulate.ai/llms.txt > Use this file to discover all available pages before exploring further. # Audio Event Detection Batch > Detect non-speech sound events in an audio file. Returns a probability for each event confidently detected, plus the audio duration, in a single synchronous response. ## OpenAPI ````yaml api/velma_2_audio_event_classifier.yaml POST /api/velma-2-audio-event-classifier openapi: 3.1.0 info: title: Velma 2 Audio Event Detection API version: 0.0.0 description: > Audio event detection via HTTP POST. Submit an audio file, get back a single JSON response with a probability for each supported event and the audio duration. Detects crying, laughter, acoustic guitar, applause, bark, bass drum, burping, bus, cello, chime, clarinet, computer keyboard, cough, cowbell, double bass, drawer open/close, electric piano, fart, finger snapping, fireworks, flute, glockenspiel, gong, gunshot/gunfire, harmonica, hi-hat, keys jangling, knock, meow, microwave oven, oboe, saxophone, scissors, shatter, snare drum, squeak, tambourine, tearing, telephone, trumpet, violin/fiddle, writing. No transcription, diarization, or PII/PHI tagging. servers: - url: https://platform.modulate.ai description: Modulate Audio Event Detection Server security: - ApiKeyAuth: [] paths: /api/velma-2-audio-event-classifier: post: summary: Detect audio events in an audio file description: | Accepts a single audio file and returns a probability for each supported event as a synchronous JSON response. operationId: detectEvents requestBody: required: true content: multipart/form-data: schema: type: object required: - upload_file properties: upload_file: type: string format: binary description: | Audio file to analyze. Must be non-empty and of a supported format. Supported formats: AAC, AIFF, FLAC, MP3, MP4, MOV, OGG, Opus, WAV, WebM. Maximum file size: 100 MB. responses: '200': description: Event detection completed successfully. content: application/json: schema: $ref: '#/components/schemas/EventDetectionResponse' examples: co_occurring_events: summary: Clip containing both applause and laughter value: probs: Applause: 0.998 Laughter: 0.946 duration_ms: 2000 crying_detected: summary: Clip containing crying value: probs: Crying: 0.94 duration_ms: 14253 no_event_detected: summary: Clip with no confidently detected event value: probs: {} duration_ms: 5400 '400': description: > Bad request - the uploaded file is empty, its format is not supported, or the audio could not be decoded. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: invalid_format: summary: Invalid file format value: detail: >- Unsupported file format. Supported formats: .aac, .aiff, .flac, .mp3, .mp4, .mov, .ogg, .opus, .wav, .webm. empty_file: summary: Empty file value: detail: The uploaded file is empty. unprocessable: summary: Audio could not be decoded value: detail: >- The audio could not be processed. It may be corrupted or in an unsupported format. bad_value: summary: Malformed request value value: detail: Invalid request. '401': description: Unauthorized - the API key was not recognized. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: Invalid API key. '403': description: Forbidden - the request is not permitted. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: not_permitted: summary: Request not permitted value: detail: This request is not permitted. model_access_denied: summary: API key lacks access to this model value: detail: This API key does not have access to this model. '413': description: Payload too large - the uploaded file exceeds the maximum file size. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: The uploaded file is too large. '422': description: > Unprocessable entity - a required request parameter is missing or invalid (for example, the `X-API-Key` header or the `upload_file` field). content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' '429': description: >- Too many requests - insufficient credits or a usage limit was reached. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: insufficient_credits: summary: Insufficient credits value: detail: Insufficient credits. concurrency_limit: summary: Concurrent request limit reached value: detail: >- Concurrent request limit reached. Please retry after your in-flight requests complete. monthly_limit: summary: Monthly usage limit reached value: detail: Monthly usage limit reached. '500': description: Internal server error during processing. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: Internal server error '503': description: Service unavailable - the service is temporarily unavailable. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: >- The service is temporarily unavailable. Please try again later. '504': description: Gateway timeout - processing timed out. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: The request timed out. Please try again. security: - ApiKeyAuth: [] components: schemas: EventDetectionResponse: type: object required: - probs - duration_ms properties: probs: type: object description: | Per-event probabilities, each between 0 and 1. Only events confidently detected in the audio are included - an omitted event was not detected with sufficient confidence, which does not necessarily mean it is absent from the audio. Included events are not mutually exclusive, and the set of included probabilities is not expected to sum to 1. `probs` is an empty object when no event was confidently detected. properties: Crying: type: number minimum: 0 maximum: 1 description: Probability that the audio contains crying. example: 0.94 Acoustic_guitar: type: number minimum: 0 maximum: 1 description: Probability that the audio contains an acoustic guitar. Applause: type: number minimum: 0 maximum: 1 description: Probability that the audio contains applause. Bark: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a dog bark. Bass_drum: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a bass drum. Burping_or_eructation: type: number minimum: 0 maximum: 1 description: Probability that the audio contains burping. Bus: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a bus. Cello: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a cello. Chime: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a chime. Clarinet: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a clarinet. Computer_keyboard: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a computer keyboard. Cough: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a cough. Cowbell: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a cowbell. Double_bass: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a double bass. Drawer_open_or_close: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a drawer opening or closing. Electric_piano: type: number minimum: 0 maximum: 1 description: Probability that the audio contains an electric piano. Fart: type: number minimum: 0 maximum: 1 description: Probability that the audio contains flatulence. Finger_snapping: type: number minimum: 0 maximum: 1 description: Probability that the audio contains finger snapping. Fireworks: type: number minimum: 0 maximum: 1 description: Probability that the audio contains fireworks. Flute: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a flute. Glockenspiel: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a glockenspiel. Gong: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a gong. Gunshot_or_gunfire: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a gunshot. Harmonica: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a harmonica. Hi_hat: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a hi-hat cymbal. Keys_jangling: type: number minimum: 0 maximum: 1 description: Probability that the audio contains keys jangling. Knock: type: number minimum: 0 maximum: 1 description: Probability that the audio contains knocking. Laughter: type: number minimum: 0 maximum: 1 description: Probability that the audio contains laughter. example: 0.94 Meow: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a cat meowing. Microwave_oven: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a microwave oven. Oboe: type: number minimum: 0 maximum: 1 description: Probability that the audio contains an oboe. Saxophone: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a saxophone. Scissors: type: number minimum: 0 maximum: 1 description: Probability that the audio contains scissors cutting. Shatter: type: number minimum: 0 maximum: 1 description: Probability that the audio contains glass shattering. Snare_drum: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a snare drum. Squeak: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a squeak. Tambourine: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a tambourine. Tearing: type: number minimum: 0 maximum: 1 description: Probability that the audio contains paper or fabric tearing. Telephone: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a ringing telephone. Trumpet: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a trumpet. Violin_or_fiddle: type: number minimum: 0 maximum: 1 description: Probability that the audio contains a violin. Writing: type: number minimum: 0 maximum: 1 description: >- Probability that the audio contains writing (e.g. with a pen or pencil). duration_ms: type: integer minimum: 0 description: | The total duration of the processed audio in milliseconds. example: 14253 ErrorResponse: type: object required: - detail properties: detail: type: string description: Human-readable error message. HTTPValidationError: type: object properties: detail: type: array items: $ref: '#/components/schemas/ValidationError' ValidationError: type: object required: - loc - msg - type properties: loc: type: array items: anyOf: - type: string - type: integer msg: type: string type: type: string securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-Key description: API key used for authentication and usage tracking. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.