====== HTTP/STT/ASR Protocol ======

===== Description =====

The Voximal VoiceXML browser can connect to a STT (SpeechToText) or ASR engines using HTTP.
The HTTP protocol is used to recognize or transcribe an audio file to a text or word(s).
 

This protocol is simple :
  * From the VoiceXML browser, you configure to use HTTP, a (POST only) request containing mainly the audio file content and additional parameters (like language, grammar, confidence level...).
  * The web server with the STT/ASR engine treats your request.
  * The VoiceXML browser receives an XML or JSON results : it converts to NLSML syntax and interpretes it.


===== Voximal configuration =====

The configuration is set in /etc/asterisk/voximal.conf, in the section "[recognizer]" :

  * **uri** : You need to set the 'uri' for the TTS (or TextToVideo) service (our scripts install the services in http://ip/stt/provider/stt.php).
  * **api** : Configure the HTTP specific API (microsoft, google, ibm/watson...).
  * **key** : Configure the authentification key API if requested by the API.


Configuration example :

<code>

[recognize]
api=microsoft
key=c49db9de7db94d50b85c0cc8c46c2651

</code>

Most of this parameters can be change from the VoiceXML syntax using properties. Use the property name 'prompt' added with the parameter name.

VoiceXML example :

<code>
<property name="promptvoice" value="Poala"/>
</code>

===== HTTP Parameters ====

  * **[body]** : the audio file : standard POST methode.
  * **language** : the language used (en-GB, fr-FR...) : from the xml:lang attribut.
  * **uid** : Voximal UID.