> ## Documentation Index > Fetch the complete documentation index at: https://docs.wavix.com/llms.txt > Use this file to discover all available pages before exploring further. # Call streaming > Bidirectional WebSocket channel for call audio streaming. Wavix opens the connection when a stream starts and closes it when the call ends. ## AsyncAPI ````yaml https://wavix.github.io/wavix-openapi/wavix-asyncapi.yaml callStreaming id: callStreaming title: Call streaming description: > Bidirectional WebSocket channel for call audio streaming. Wavix opens the connection when a stream starts and closes it when the call ends. servers: - id: externalService protocol: wss host: '{serviceHost}' bindings: [] variables: - id: serviceHost description: Hostname of the external WebSocket service. allowedValues: [] examples: [] - id: servicePath description: Path of the external WebSocket service. allowedValues: [] examples: [] address: '{servicePath}' parameters: [] bindings: [] operations: - &ref_6 id: sendConnected title: Send connected description: Send a connection event. type: send messages: - &ref_14 id: ConnectedEvent payload: - name: connected description: Connection established. type: object properties: - name: event type: string description: Event type. required: true - name: event_time type: string description: ISO 8601 timestamp of the event. required: true headers: [] jsonPayloadSchema: type: object required: - event - event_time properties: event: type: string const: connected description: Event type. x-parser-schema-id: event_time: &ref_0 type: string format: date-time description: ISO 8601 timestamp of the event. x-parser-schema-id: EventTime x-parser-schema-id: ConnectedEvent title: connected description: Connection established. example: |- { "event": "connected", "event_time": "2024-01-15T10:30:00Z" } bindings: [] extensions: - id: x-parser-unique-object-id value: ConnectedEvent bindings: [] extensions: &ref_1 - id: x-parser-unique-object-id value: callStreaming - &ref_7 id: sendStart title: Send start description: Send a start event. type: send messages: - &ref_15 id: StartEvent payload: - name: start description: Stream started. type: object properties: - name: event type: string description: Event type. required: true - name: event_time type: string description: ISO 8601 timestamp of the event. required: true - name: call_id type: string description: Unique identifier for the call. required: true - name: stream_id type: string description: Unique identifier for the stream. required: true - name: stream_type type: string description: > Direction of audio flow. `oneway` means audio flows from the call to the external service. `twoway` means audio flows in both directions. enumValues: - oneway - twoway required: true - name: channel type: string description: Call leg from which Wavix captures audio. enumValues: - inbound - outbound - both required: true - name: sequence_number type: integer description: Sequential event counter for the stream, starting at 1. required: true headers: [] jsonPayloadSchema: type: object required: - event - event_time - call_id - stream_id - stream_type - channel - sequence_number properties: event: type: string const: start description: Event type. x-parser-schema-id: event_time: *ref_0 call_id: type: string description: Unique identifier for the call. x-parser-schema-id: stream_id: type: string description: Unique identifier for the stream. x-parser-schema-id: stream_type: type: string enum: - oneway - twoway description: > Direction of audio flow. `oneway` means audio flows from the call to the external service. `twoway` means audio flows in both directions. x-parser-schema-id: channel: type: string enum: - inbound - outbound - both description: Call leg from which Wavix captures audio. x-parser-schema-id: sequence_number: type: integer format: int64 description: Sequential event counter for the stream, starting at 1. x-parser-schema-id: example: event: start event_time: '2024-01-15T10:30:00Z' call_id: abc-123 stream_id: str-456 stream_type: twoway channel: both sequence_number: 1 x-parser-schema-id: StartEvent title: start description: Stream started. example: |- { "event": "start", "event_time": "2024-01-15T10:30:00Z", "call_id": "abc-123", "stream_id": "str-456", "stream_type": "twoway", "channel": "both", "sequence_number": 1 } bindings: [] extensions: - id: x-parser-unique-object-id value: StartEvent bindings: [] extensions: *ref_1 - &ref_8 id: sendMedia title: Send media description: Send call audio. type: send messages: - &ref_16 id: OutgoingMediaEvent payload: - name: media description: Audio chunk captured from the call. type: object properties: - name: event type: string description: Event type. required: true - name: event_time type: string description: ISO 8601 timestamp of the event. required: true - name: call_id type: string description: Unique identifier for the call. required: true - name: stream_id type: string description: Unique identifier for the stream. required: true - name: sequence_number type: integer description: Sequential event counter for the stream, starting at 1. required: true - name: media type: object required: true properties: - name: payload type: string description: Base64-encoded audio chunk. required: true - name: track type: string description: Call leg from which the audio was captured. enumValues: - inbound - outbound required: true - name: timestamp type: integer description: RTP timestamp of the audio chunk. required: true - name: chunk type: integer description: Sequential chunk number within the stream, starting at 1. required: true headers: [] jsonPayloadSchema: type: object required: - event - event_time - call_id - stream_id - sequence_number - media properties: event: type: string const: media description: Event type. x-parser-schema-id: event_time: *ref_0 call_id: type: string description: Unique identifier for the call. x-parser-schema-id: stream_id: type: string description: Unique identifier for the stream. x-parser-schema-id: sequence_number: type: integer format: int64 description: Sequential event counter for the stream, starting at 1. x-parser-schema-id: media: type: object required: - payload - track - timestamp - chunk properties: payload: type: string description: Base64-encoded audio chunk. x-parser-schema-id: track: type: string enum: - inbound - outbound description: Call leg from which the audio was captured. x-parser-schema-id: timestamp: type: integer format: int64 description: RTP timestamp of the audio chunk. x-parser-schema-id: chunk: type: integer format: int64 description: Sequential chunk number within the stream, starting at 1. x-parser-schema-id: x-parser-schema-id: OutgoingMediaPayload example: event: media event_time: '2024-01-15T10:30:01Z' call_id: abc-123 stream_id: str-456 sequence_number: 2 media: payload: AAEC/f7... track: inbound timestamp: 160 chunk: 1 x-parser-schema-id: OutgoingMediaEvent title: media description: Audio chunk captured from the call. example: |- { "event": "media", "event_time": "2024-01-15T10:30:01Z", "call_id": "abc-123", "stream_id": "str-456", "sequence_number": 2, "media": { "payload": "AAEC/f7...", "track": "inbound", "timestamp": 160, "chunk": 1 } } bindings: [] extensions: - id: x-parser-unique-object-id value: OutgoingMediaEvent bindings: [] extensions: *ref_1 - &ref_9 id: sendMark title: Send mark description: Send a playback acknowledgment. type: send messages: - &ref_17 id: OutgoingMarkEvent payload: - name: mark description: Playback acknowledgment for the preceding media message. type: object properties: - name: event type: string description: Event type. required: true - name: event_time type: string description: ISO 8601 timestamp of the event. required: true - name: call_id type: string description: Unique identifier for the call. required: true - name: stream_id type: string description: Unique identifier for the stream. required: true - name: sequence_number type: integer description: Sequential event counter for the stream, starting at 1. required: true - name: mark type: object required: true properties: - name: name type: string description: > Echo of the marker name from the original outgoing `mark` message. Wavix sends this message when playback is complete. required: true headers: [] jsonPayloadSchema: type: object required: - event - event_time - call_id - stream_id - sequence_number - mark properties: event: type: string const: mark description: Event type. x-parser-schema-id: event_time: *ref_0 call_id: type: string description: Unique identifier for the call. x-parser-schema-id: stream_id: type: string description: Unique identifier for the stream. x-parser-schema-id: sequence_number: type: integer format: int64 description: Sequential event counter for the stream, starting at 1. x-parser-schema-id: mark: type: object required: - name properties: name: type: string description: > Echo of the marker name from the original outgoing `mark` message. Wavix sends this message when playback is complete. x-parser-schema-id: example: name: end-of-greeting x-parser-schema-id: OutgoingMarkPayload example: event: mark event_time: '2024-01-15T10:30:02Z' call_id: abc-123 stream_id: str-456 sequence_number: 10 mark: name: end-of-greeting x-parser-schema-id: OutgoingMarkEvent title: mark description: Playback acknowledgment for the preceding media message. example: |- { "event": "mark", "event_time": "2024-01-15T10:30:02Z", "call_id": "abc-123", "stream_id": "str-456", "sequence_number": 10, "mark": { "name": "end-of-greeting" } } bindings: [] extensions: - id: x-parser-unique-object-id value: OutgoingMarkEvent bindings: [] extensions: *ref_1 - &ref_10 id: sendStop title: Send stop description: Send a stop event. type: send messages: - &ref_18 id: StopEvent payload: - name: stop description: Stream ended. type: object properties: - name: event type: string description: Event type. required: true - name: event_time type: string description: ISO 8601 timestamp of the event. required: true - name: call_id type: string description: Unique identifier for the call. required: true - name: stream_id type: string description: Unique identifier for the stream. required: true - name: sequence_number type: integer description: Sequential event counter for the stream, starting at 1. required: true headers: [] jsonPayloadSchema: type: object required: - event - event_time - call_id - stream_id - sequence_number properties: event: type: string const: stop description: Event type. x-parser-schema-id: event_time: *ref_0 call_id: type: string description: Unique identifier for the call. x-parser-schema-id: stream_id: type: string description: Unique identifier for the stream. x-parser-schema-id: sequence_number: type: integer format: int64 description: Sequential event counter for the stream, starting at 1. x-parser-schema-id: example: event: stop event_time: '2024-01-15T10:30:05Z' call_id: abc-123 stream_id: str-456 sequence_number: 100 x-parser-schema-id: StopEvent title: stop description: Stream ended. example: |- { "event": "stop", "event_time": "2024-01-15T10:30:05Z", "call_id": "abc-123", "stream_id": "str-456", "sequence_number": 100 } bindings: [] extensions: - id: x-parser-unique-object-id value: StopEvent bindings: [] extensions: *ref_1 - &ref_3 id: receiveMedia title: Receive media description: Receive audio for playback. type: receive messages: - &ref_11 id: IncomingMediaEvent payload: - name: media description: Audio chunk to play back into the call. type: object properties: - name: event type: string description: Event type. required: true - name: stream_id type: string description: > If omitted, the event applies to the stream associated with the connection that initiated the WebSocket session. Include `stream_id` to enable server-side validation. Events with a mismatched `stream_id` are silently dropped. required: false - name: media type: object required: true properties: - name: payload type: string description: Base64-encoded PCM16 audio to play into the call. required: true headers: [] jsonPayloadSchema: type: object required: - event - media properties: event: type: string const: media description: Event type. x-parser-schema-id: stream_id: &ref_2 type: string description: > If omitted, the event applies to the stream associated with the connection that initiated the WebSocket session. Include `stream_id` to enable server-side validation. Events with a mismatched `stream_id` are silently dropped. x-parser-schema-id: IncomingStreamId media: type: object required: - payload properties: payload: type: string description: Base64-encoded PCM16 audio to play into the call. x-parser-schema-id: x-parser-schema-id: IncomingMediaPayload example: event: media stream_id: str-456 media: payload: BBCD/e... x-parser-schema-id: IncomingMediaEvent title: media description: Audio chunk to play back into the call. example: |- { "event": "media", "stream_id": "str-456", "media": { "payload": "AAEC/f7..." } } bindings: [] extensions: - id: x-parser-unique-object-id value: IncomingMediaEvent bindings: [] extensions: *ref_1 - &ref_4 id: receiveMark title: Receive mark description: Receive a playback marker. type: receive messages: - &ref_12 id: IncomingMarkEvent payload: - name: mark description: Marker used to track playback completion. type: object properties: - name: event type: string description: Event type. required: true - name: stream_id type: string description: > If omitted, the event applies to the stream associated with the connection that initiated the WebSocket session. Include `stream_id` to enable server-side validation. Events with a mismatched `stream_id` are silently dropped. required: false - name: mark type: object required: true properties: - name: name type: string description: Marker name used to track playback completion. required: true headers: [] jsonPayloadSchema: type: object required: - event - mark properties: event: type: string const: mark description: Event type. x-parser-schema-id: stream_id: *ref_2 mark: type: object required: - name properties: name: type: string description: Marker name used to track playback completion. x-parser-schema-id: x-parser-schema-id: IncomingMarkPayload example: event: mark stream_id: str-456 mark: name: end-of-greeting x-parser-schema-id: IncomingMarkEvent title: mark description: Marker used to track playback completion. example: |- { "event": "mark", "stream_id": "str-456", "mark": { "name": "mark-1" } } bindings: [] extensions: - id: x-parser-unique-object-id value: IncomingMarkEvent bindings: [] extensions: *ref_1 - &ref_5 id: receiveClear title: Receive clear description: Receive a clear event. type: receive messages: - &ref_13 id: ClearEvent payload: - name: clear description: Clear buffered audio. type: object properties: - name: event type: string description: Event type. required: true - name: stream_id type: string description: > If omitted, the event applies to the stream associated with the connection that initiated the WebSocket session. Include `stream_id` to enable server-side validation. Events with a mismatched `stream_id` are silently dropped. required: false headers: [] jsonPayloadSchema: type: object required: - event properties: event: type: string const: clear description: Event type. x-parser-schema-id: stream_id: *ref_2 example: event: clear stream_id: str-456 x-parser-schema-id: ClearEvent title: clear description: Clear buffered audio. example: |- { "event": "clear", "stream_id": "str-456" } bindings: [] extensions: - id: x-parser-unique-object-id value: ClearEvent bindings: [] extensions: *ref_1 sendOperations: - *ref_3 - *ref_4 - *ref_5 receiveOperations: - *ref_6 - *ref_7 - *ref_8 - *ref_9 - *ref_10 sendMessages: - *ref_11 - *ref_12 - *ref_13 receiveMessages: - *ref_14 - *ref_15 - *ref_16 - *ref_17 - *ref_18 extensions: - id: x-parser-unique-object-id value: callStreaming securitySchemes: [] ````