Appendix A: Audio Files & Call Control XML

Using Audio files in CCXML is obviously not going to be very prevalent; most audio output will be coded into any VoiceXML dialogs that you reference. However, you do have the option to specify an audio file within the <dialogstart> element:


  <dialogstart src="'MyFile.wav'" type="'audio/wav'"/>

You also have the option of using Voxeo's own extensions to the w3c specification should you wish to playback an audio file. For instance, you could use the 'application/x-fetchdigits' as a <dialogstart type>. Let's take a look at the following snippet to see how this might play out:


   ...
 <dialogstart src="'http://MyServer.com/MyFile.wav?termdigits=#'" 
  type="'application/x-fetchdigits'" name="SomeName"/>
    ...

For more information, please see the Appendix containing Voxeo's extension elements.

Audio Formats

The supported audio formats for the CCXML markup are as follows:

8bit 8kHz mulaw mono .wav files
8bit 8kHz mulaw mono . vox files

It is recommended that you keep your audio prompts as 'universal' as possible, therefore, we advise that you stick with the 8bit/8kHz wav format, which is supported on all telephony platforms and gateways.

Voxeo Audio Library

Voxeo has anticipated your audio needs, and has a bountiful selection of professional prerecorded audio files available for download, free of charge. These audio files are in 8,000 Hz, 8 bit, MuLaw .wav format, which you can download right here!

These recorded prompts cover the following:

airport codes
alphabet
common Navigation
credit card
currency
dtmf tones
dates and times
greeting files
math
numbers
PIN
common prepositions
press digits
telephone
voicemail prompts

Audio Tools

If you are not certain how to go about getting your files in the proper format, Windows users can use the Sound Recorder to check the file and make changes to it; simply open the file, then select "File" "Save as"..., press the "Change..." button, and change the attributes to "8,000 Hz, 8 Bit, Mono" and you should be ready to launch. However, for the folks that prefer more powerful sound editing software, there are a number of freeware programs that can fit the bill. A listing, (by no means complete), of some good offerings are as follows:

Audio Links

If you are looking for professional voice talent for your application, and you don't see files that meet your specific needs in our download library, you would do well to contact:

GreatVoice.com

Recording Audio

You do have the ability to record audio within the CCXML portion of your code, should you desire. For this, you would want to use the Voxeo extension attributes to the <dialogstart> element. Targets can be any .wav or .vox sound file on HTTP or FTP servers, and we can pass along a number of URL parameters to fine-tune the recording session. Taking a look at the following snippet will give us an indication of how this might look in action:


  ...
  <dialogstart src="'ftp://Myserver.com/MyAudioFile.wav?termdigits=1'" 
                      type="'application/x-recordaudio'" name="SomeName"/>"  ...

The URL parameters that you can supply to this extension are as follows:

termdigits: determines which DTMF tones stop the recording (default:"")
format: specifies the MIME type (default: "audio/wav")
maxtime: the maximum number of milliseconds the recording session should last (default: 30000)
maxsilence: maximum number of milliseconds of silence allowed before the recording session is terminated (default: 5000)
beep: "true" to play an initial beep, "false" if not desired (default: "true")
cleardigits: "true" to flush the digit buffer before recording, "false" to leave it as-is (default: "false")

Also note that you may use either a fully qualified URL for the 'src' attribute, or you may use a relative one. Also note that for HTTP uploads, the default method is "GET", which may require special configurations on some webservers.

ANNOTATIONS: EXISTING POSTS

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Using JSON, Send, and Foreach

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