AGI Asterisk IBM Watson Service Speech to Text (python)

Introduction

The Asterisk Gateway Interface is an interface for adding functionality to Asterisk with many different programming languages. In this case, we will integrate Asterisk with IBM Watson service to transcribe audio to text.

This python script receives one parameter (audio file) and returns the associated text through standard output.

Execution example

python -W ignore audio_parser.py custom-record0

Source Code

#!/usr/bin/python
# Overall import
import sys,os
import requests
import json

## Watson Parameters
# Credentials
username = "XXXXX"
password = "XXXXX"
# Model language
model_name = "es-ES_NarrowbandModel"
# API Url Endpoint
url = "https://stream.watsonplatform.net/speech-to-text/api/v1/recognize?continuous=true&model=" + model_name
# Timeout API
timeout = 5

## Audio Parameters
path_audio = "/var/lib/asterisk/sounds"
ext_audio = "wav"

## Init VariablesA
# Default event
event = "SOPORTE"

# Obtain audio file
data = open(path_audio + "/" + sys.argv[1] + "." + ext_audio)

# Send Data 
def send(data):
    sys.stdout.write(str(data))
    sys.stdout.flush()

# Call Watson API
def call_watson(url, data, username, password, timeout):
    try:
    	headers = {'content-type': 'audio/' + ext_audio}
    	r = requests.post(url=url,auth=(username, password),data=data,headers=headers,timeout=timeout)
    except (requests.exceptions.Timeout, requests.exceptions.TooManyRedirects, requests.exceptions.RequestException) as e:
    # Handler Exception
	return "ERROR" 
    # Return Error    
    return json.dumps(r.json())

# Call API Watson
res = call_watson(url, data, username, password, timeout)

if res != "ERROR":
    a = json.loads(res)
    # Return transcript
    text = a["results"][0]["alternatives"][0]["transcript"]
    msg = text.encode('ascii', 'ignore').decode('ascii')
    event = "XXXX"
else:
    event = "ERROR"
    

## Asterisk AGI
# Send Event
send("SET VARIABLE SPEECH_TO_TEXT " + event)