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Class: PlivoMediaStreamParser

Defined in: packages/agentos/src/channels/telephony/parsers/PlivoMediaStreamParser.ts:68

Parses the Plivo Audio Stream WebSocket protocol.

Plivo sends JSON-encoded messages for stream lifecycle events (start, stop) and audio chunks (media). The audio payload is base64-encoded mu-law PCM, delivered in a payload field inside the media object.

Outgoing audio is wrapped in a playAudio JSON envelope, which is the format Plivo expects when the server streams audio back to the caller. No explicit connection acknowledgment is required after the handshake.

See​

https://www.plivo.com/docs/voice/xml/stream

Implements​

Constructors​

Constructor​

new PlivoMediaStreamParser(): PlivoMediaStreamParser

Returns​

PlivoMediaStreamParser

Methods​

formatOutgoing()​

formatOutgoing(audio, _streamSid): string

Defined in: packages/agentos/src/channels/telephony/parsers/PlivoMediaStreamParser.ts:156

Encode mu-law audio for transmission back to Plivo.

Plivo requires audio to be base64-encoded and wrapped in a playAudio JSON envelope. Unlike Twilio, the streamSid / stream_id is NOT included in the outbound message -- Plivo implicitly routes the audio to the caller on the same WebSocket connection.

Parameters​

audio​

Buffer

Raw mu-law PCM bytes to send to the caller.

_streamSid​

string

Unused by Plivo's playAudio format (accepted for interface parity with other parsers).

Returns​

string

JSON string: { event: 'playAudio', media: { payload: '<base64>' } }

Implementation of​

MediaStreamParser.formatOutgoing

parseIncoming()​

parseIncoming(data): MediaStreamIncoming | null

Defined in: packages/agentos/src/channels/telephony/parsers/PlivoMediaStreamParser.ts:87

Parse a raw WebSocket frame from Plivo's audio stream.

Supported Plivo event types:

  • start -- stream established; stream_id maps to streamSid, call_uuid maps to callSid.
  • media -- audio chunk; media.payload contains base64-encoded mu-law PCM bytes.
  • stop -- stream ended (call terminated or stream explicitly closed).

Any other event type is silently dropped by returning null. Malformed JSON or messages missing required fields (event, stream_id) also return null.

Parameters​

data​

Raw WebSocket frame payload (JSON string or Buffer from Plivo).

string | Buffer

Returns​

MediaStreamIncoming | null

Normalised MediaStreamIncoming event, or null for unknown event types or malformed messages.

Implementation of​

MediaStreamParser.parseIncoming