Free VoiceXML Resource by C.a.T.S.

<www.vxml.co.za>

<training>

<voicexml tutorial>

Voice Messaging

Record Voice

Below is a working example of a form which requests the user to speak a message which will be recorded. Confirmation is given to the caller if the recording is successful, and the call is terminated if the conditions are not met. Voice recordings must be submitted to a web page and cannot always be saved on the platform.

The conditions are:

- The maximum recording time is 60 seconds
- The recording attempt will be terminated with a DTMF key
- A beep will be played once recording can commence

<form id="record">
      <record name="personal_greeting"
            maxtime="60s" dtmfterm="true" beep="true">
<!-- The recording conditions are set  -->

         <prompt>
            At the tone, please record your personal greeting.
            When you're done, press the hash key.
         </prompt>
<!-- The instructions are played to the caller -->

         		<filled>
         			<prompt>
         				I have received recorded audio from this call.
         			</prompt>
         		</filled>
<!-- If The conditions of the form are met, we play this  -->

         		<noinput>
         		Sorry. I didn't hear you. Now returning to the main menu.
         		<exit />
         		</noinput>
<!-- If there is not suitable input, we play the following -->
      </record>
</form>

Playback Voice

The playback of the recorded voice can be done as per the next example. Take note that the recording is still in the workspace and once the call is terminated, the recording will be lost, unless the recoding is stored.

</record>
<!-- The playback routine can be placed here below the record element -->

   <!-- Playback of the recording takes place here -->
      <block>
         <prompt>
            Here is what your recording sounds like.
            <audio expr="personal_greeting"/>
         </prompt>
      </block>

Save Voice Recording

A script will be needed on a web/application server which can be accessed by the VXML application and used to deposit the recording.

Herewith an example of such a script in PHP:

<?php
header('Content-type: application/voicexml+xml; charset=iso-8859-1');
header('Content-Encoding: iso-8859-1');
echo "<?xml version=\"1.0\" encoding=\"iso-8859-1\"?>\n";
$msg = "";
$code = 1;
$tmpFile=$HTTP_POST_FILES['personal_greeting']['tmp_name'];
if (is_uploaded_file($tmpFile))
{
  $wavfile="wav/".date("YmdHis").".wav";
  copy($tmpFile, sprintf("%s",$wavfile));
$msg = "audio saved";
}
else
{
  $code = 0;
  $msg = "unable to save audio";
}
print "<vxml version=\"2.0\" xmlns=\"http://www.w3.org/2001/vxml\" xml:lang=\"en-US\">\n";
#print "<menu>\n";
#print "<prompt>\n";
#print "test\n";
#print "</prompt>\n";
#print "</menu>\n";
print "<form>\n";
print "<var name=\"code\" expr=\"'.$code'\"/>\n";
print "<var name=\"msg\" expr=\"'.$msg'\"/>\n";
print "<block>\n";
print "<return namelist=\"code msg\"/>\n";
print "</block>\n";
print "</form>\n";
print "</vxml>\n";
?>
<!-- <vxml version="2.0" xmlns="http://www.w3.org/2001/vxml" xml:lang="en-US"> -->
<!-- <form> -->
<!-- <var name="code" expr=".$code"/> -->
<!-- <var name="msg" expr="'.$msg'"/> -->
<!-- <block> -->
<!-- <return namelist="code msg"/> -->
<!-- </block></form></vxml> -->

The VXML portion that will facilitate the interaction with the PHP code can look as follow:

      <block>
         <prompt>
            Here's what callers will hear.
            <audio expr="personal_greeting"/>
         </prompt>

<!-- This block plays the recorded message back to the caller  -->

      </block>
      	 
<block>
        <submit next="http://www.10.0.0.0/vxml/record.php" enctype="multipart/form-data"  namelist="personal_greeting" method="post" maxage="0"/>
        <exit/>
        </block>
<!-- This block sends the recording to the URL and plays the return value.  -->

It is up to the developer to develop an interface, via the web or otherwise, to access the recordings on his/her web/application server and also handle the administration of that. Hence, the recording capturing, archiving and management falls 100% outside the domain of the telco. When it comes to saving recordings, careful consideration must be given to the call volume expected, and the amount of data that would be sent to the web/application server at any given time. Hence bandwidth considerations are of paramount importance to avoid a bottle neck and a subsequent failure of the service.

It would make sense to have a dedicated line with fixed bandwidth to ensure quality of service.

Now we can go to:
Advanced Topics