> ## 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 every supported event, 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 English 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 English Audio Event Detection Server security: - ApiKeyAuth: [] paths: /api/velma-2-audio-event-classifier: post: summary: Detect audio events in an English audio file description: | Accepts a single audio file and returns a probability for each supported event as a synchronous JSON response. operationId: detectEventsEnglish 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: laughter_detected: summary: Clip containing laughter value: probs: cry: 0.01 Acoustic_guitar: 0.002 Applause: 0.03 Bark: 0.001 Bass_drum: 0.001 Burping_or_eructation: 0.002 Bus: 0.001 Cello: 0.001 Chime: 0.001 Clarinet: 0.001 Computer_keyboard: 0.001 Cough: 0.01 Cowbell: 0.001 Double_bass: 0.001 Drawer_open_or_close: 0.001 Electric_piano: 0.001 Fart: 0.002 Finger_snapping: 0.005 Fireworks: 0.001 Flute: 0.001 Glockenspiel: 0.001 Gong: 0.001 Gunshot_or_gunfire: 0.001 Harmonica: 0.001 Hi-hat: 0.001 Keys_jangling: 0.001 Knock: 0.002 Laughter: 0.913 Meow: 0.001 Microwave_oven: 0.001 Oboe: 0.001 Saxophone: 0.001 Scissors: 0.001 Shatter: 0.001 Snare_drum: 0.001 Squeak: 0.001 Tambourine: 0.001 Tearing: 0.001 Telephone: 0.002 Trumpet: 0.001 Violin_or_fiddle: 0.001 Writing: 0.001 duration_ms: 2000 crying_detected: summary: Clip containing crying value: probs: cry: 0.94 Acoustic_guitar: 0.0244 Applause: 0.0244 Bark: 0.0244 Bass_drum: 0.0244 Burping_or_eructation: 0.0244 Bus: 0.0244 Cello: 0.0244 Chime: 0.0244 Clarinet: 0.0244 Computer_keyboard: 0.0244 Cough: 0.0244 Cowbell: 0.0244 Double_bass: 0.0244 Drawer_open_or_close: 0.0244 Electric_piano: 0.0244 Fart: 0.0244 Finger_snapping: 0.0244 Fireworks: 0.0244 Flute: 0.0244 Glockenspiel: 0.0244 Gong: 0.0244 Gunshot_or_gunfire: 0.0244 Harmonica: 0.0244 Hi-hat: 0.0244 Keys_jangling: 0.0244 Knock: 0.0244 Laughter: 0.0244 Meow: 0.0244 Microwave_oven: 0.0244 Oboe: 0.0244 Saxophone: 0.0244 Scissors: 0.0244 Shatter: 0.0244 Snare_drum: 0.0244 Squeak: 0.0244 Tambourine: 0.0244 Tearing: 0.0244 Telephone: 0.0244 Trumpet: 0.0244 Violin_or_fiddle: 0.0244 Writing: 0.0244 duration_ms: 14253 '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. '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. `cry` is predicted independently. `Laughter` and every other entry are drawn from a single shared distribution. required: - cry - Acoustic_guitar - Applause - Bark - Bass_drum - Burping_or_eructation - Bus - Cello - Chime - Clarinet - Computer_keyboard - Cough - Cowbell - Double_bass - Drawer_open_or_close - Electric_piano - Fart - Finger_snapping - Fireworks - Flute - Glockenspiel - Gong - Gunshot_or_gunfire - Harmonica - Hi-hat - Keys_jangling - Knock - Laughter - Meow - Microwave_oven - Oboe - Saxophone - Scissors - Shatter - Snare_drum - Squeak - Tambourine - Tearing - Telephone - Trumpet - Violin_or_fiddle - Writing properties: cry: type: number minimum: 0 maximum: 1 description: Probability that the audio contains crying. example: 0.03 Acoustic_guitar: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is an acoustic guitar. Applause: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is applause. Bark: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a dog bark. Bass_drum: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a bass drum. Burping_or_eructation: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is burping. Bus: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a bus. Cello: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a cello. Chime: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a chime. Clarinet: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a clarinet. Computer_keyboard: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a computer keyboard. Cough: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a cough. Cowbell: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a cowbell. Double_bass: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a double bass. Drawer_open_or_close: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a drawer opening or closing. Electric_piano: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is an electric piano. Fart: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is flatulence. Finger_snapping: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is finger snapping. Fireworks: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is fireworks. Flute: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a flute. Glockenspiel: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a glockenspiel. Gong: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a gong. Gunshot_or_gunfire: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a gunshot. Harmonica: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a harmonica. Hi-hat: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a hi-hat cymbal. Keys_jangling: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is keys jangling. Knock: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is 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's primary sound event is a cat meowing. Microwave_oven: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a microwave oven. Oboe: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is an oboe. Saxophone: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a saxophone. Scissors: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is scissors cutting. Shatter: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is glass shattering. Snare_drum: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a snare drum. Squeak: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a squeak. Tambourine: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a tambourine. Tearing: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is paper or fabric tearing. Telephone: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is a ringing telephone. Trumpet: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a trumpet. Violin_or_fiddle: type: number minimum: 0 maximum: 1 description: Probability that the audio's primary sound event is a violin. Writing: type: number minimum: 0 maximum: 1 description: >- Probability that the audio's primary sound event is 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. ````