Asterisk Dialogflow RTP AudioServer

This application takes UDP audio from Asterisk sent using the External Media application in ARI, and pipes it up to Dialogflow and vice-versa. It takes messaging via MQTT to inform it of a new incoming stream with the associated source port.

Once we have transcription and intent data from Dialogflow we send it over MQTT.

Requirements

• Node 12+
• Asterisk 16.6 onwards
• Asterisk-Dialogflow-ARI-Bridge running elsewhere
• MQTT Server
• Dialogflow credentials

Install

yarn

Run

Set your config settings in config/default.js (or config/production.js if you're running with NODE_ENV=production)

yarn start

Logging

This project uses Pino as it's logging library which outputs JSON to the console. You can make this easier ot read using pino-pretty or just use the yarn start-pretty command.

Dockerfile

The included Dockerfile is very opinionated. It uses multi stage builds and then uses a "distroless" Node.js image from Google. there's no point exec'ing into it because there's no bash terminal available etc. Use it as Docker should be used :)

Working with Different Formats

Dialogflow supports a bunch of formats reference. This project has been tested to work with Linear PCM (Linear16) and Mu-law.

Linear PCM

You'll need to ensure formats used by ARI Bridge and RTP Audioserver are in sync.

Changes in rtp-audioserver

Changes in default.js

// default.js

asterisk: {
    format: 'slin16',
    audioByteSize: 320,
    packetTimestampDifference: 160,
    rtpPayloadType: 11
}

Change Dialogflow Settings,

1. Make sure audioInputConfig.audioEncoding and audioOutputConfig.audioEncoding are set to AUDIO_ENCODING_LINEAR_16 and OUTPUT_AUDIO_ENCODING_LINEAR_16

Changes in ARI Bridge

Make sure the formats defined in the configuration file of ARI Bridge is also using slin16.

Mu-law

Mu-law is headerless single channel audio with a frequency of 8000 hertz and a bit rate of 8-bits.

Changes in rtp-audioserver

Changes in default.js

// default.js

asterisk: {
    format: 'ulaw',
    audioByteSize: 160,
    packetTimestampDifference: 160,
    rtpPayloadType: 0
}

Change Dialogflow Settings,

1. Make sure dialogflow.audioInputConfig.audioEncoding and dialogflow.audioOutputConfig.audioEncoding are set to AUDIO_ENCODING_MULAW and OUTPUT_AUDIO_ENCODING_MULAW
2. Change dialogflow.audioInputConfig.sampleRateHertz to 8000.

Changes in ARI Bridge

Make sure the formats defined in the configuration file of ARI Bridge is also using ulaw.