> ## 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. # Emotion Detection Batch > Classify the emotional tone of an audio file. Returns a whole-file emotion label plus a time series of fixed-length windows, each with its own label, in a single synchronous response. ## OpenAPI ````yaml api/velma_2_emotion_batch.yaml POST /api/velma-2-emotion-batch openapi: 3.1.0 info: title: Velma 2 Emotion Batch API version: 0.0.0 description: | Batch emotion detection on an audio file via HTTP POST. Returns a single whole-file emotion label plus a time series of fixed-length windows, each with its own emotion label. ## Behavior Notes - The `time_series` entries are consecutive, fixed-length windows over the file; each entry's `start_ms` and `duration_ms` delimit its span. A trailing remainder shorter than one full window is omitted. - A file shorter than one window returns an empty `time_series`; the whole-file `emotion` is still returned. - `emotion` is always a non-null string. servers: - url: https://platform.modulate.ai description: Modulate Emotion Batch Server security: - ApiKeyAuth: [] paths: /api/velma-2-emotion-batch: post: summary: Detect emotion in an audio file description: | Analyze an audio file and return a whole-file emotion label plus a per-window emotion time series. operationId: detectEmotionBatch 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. Supported formats: AAC, AIFF, FLAC, MP3, MP4, MOV, OGG, Opus, WAV, WebM. Maximum file size: 100MB. Empty files are rejected. training_permitted: type: boolean default: true description: > Whether this request's audio may be used to improve the models. use_ensemble: type: boolean default: false description: > When true, performs a more thorough analysis that may change the returned labels and increases latency. responses: '200': description: Emotion detection completed successfully content: application/json: schema: $ref: '#/components/schemas/EmotionResponse' examples: emotion: summary: Emotion with time series value: emotion: Happy time_series: - start_ms: 0 duration_ms: 15000 emotion: Happy - start_ms: 15000 duration_ms: 15000 emotion: Neutral '400': description: | Bad request - The submitted audio was rejected: an unsupported file extension, an empty file, or audio that could not be processed (for example, corrupted data or content that does not match a supported format). 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, .mov, .mp3, .mp4, .ogg, .opus, .wav, .webm. empty_file: summary: Empty file value: detail: The uploaded file is empty. unprocessable_audio: summary: Audio could not be processed value: detail: >- The audio could not be processed. It may be corrupted or in an unsupported format. '403': description: Forbidden - the request is not permitted content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: This request is not permitted. '422': description: > Unprocessable Entity - a required request field is missing or malformed (for example, the `X-API-Key` header or the `upload_file` part). content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' '429': description: >- Too many requests - the request could not be completed due to insufficient credits content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: Insufficient credits. '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: detail: Internal server error '502': description: Bad gateway - the request could not be validated or completed content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: validation_unavailable: summary: Request could not be validated value: detail: Unable to validate request. Please try again. request_not_completed: summary: Request could not be completed value: detail: Unable to complete the request. Please try again. components: schemas: EmotionResponse: type: object required: - emotion - time_series properties: emotion: type: string description: | The emotion label for the whole file. Always present and non-null. example: Happy time_series: type: array description: | Consecutive fixed-length windows over the file, each with its own emotion label. Empty when the file is shorter than one window. items: $ref: '#/components/schemas/EmotionWindow' ErrorResponse: type: object required: - detail properties: detail: type: string description: Human-readable error message describing what went wrong example: >- The audio could not be processed. It may be corrupted or in an unsupported format. HTTPValidationError: type: object properties: detail: type: array items: $ref: '#/components/schemas/ValidationError' EmotionWindow: type: object required: - start_ms - duration_ms - emotion properties: start_ms: type: integer minimum: 0 description: | Start of this window in milliseconds from the beginning of the file. example: 0 duration_ms: type: integer minimum: 0 description: Length of this window in milliseconds. example: 15000 emotion: type: string description: The emotion label for this window. example: Happy 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. ````