support mod_vad_detect (#762)

* support mod_vad_detect

* wip

* update verb spec and drachtio fsmrf

* Update example-voicemail-greetings.json (#761)

Update voicemail english greetings

* wip

* stopvad if playdone

---------

Co-authored-by: Vinod Dharashive <vdharashive@gmail.com>

lib/tasks/config.js

@@ -15,7 +15,8 @@ class TaskConfig extends Task {
       'transcribe',
       'fillerNoise',
       'actionHookDelayAction',
-      'boostAudioSignal'
+      'boostAudioSignal',
+      'vad'
     ].forEach((k) => this[k] = this.data[k] || {});
 
     if ('notifyEvents' in this.data) {
@@ -70,6 +71,7 @@ class TaskConfig extends Task {
   get hasListen() { return Object.keys(this.listen).length; }
   get hasTranscribe() { return Object.keys(this.transcribe).length; }
   get hasDub() { return Object.keys(this.dub).length; }
+  get hasVad() { return Object.keys(this.vad).length; }
   get hasFillerNoise() { return Object.keys(this.fillerNoise).length; }
 
   get summary() {
@@ -287,6 +289,16 @@ class TaskConfig extends Task {
         cs.enableFillerNoise(opts);
       }
     }
+
+    if (this.hasVad) {
+      cs.vad = {
+        enable: this.vad.enable || false,
+        voiceMs: this.vad.voiceMs || 250,
+        silenceMs: this.vad.silenceMs || 150,
+        strategy: this.vad.strategy || 'one-shot',
+        mode: this.vad.mod || 2
+      };
+    }
   }
 
   async kill(cs) {