Plum DEV Documentation

Audio Formats and Prompts

Supported Audio Formats

The following audio formats are supported for the <audio> tag:

  • 8 kHz 16-bit linear PCM headerless (*.l16)
  • 8 kHz 8-bit µ-law encoded headerless (*.ul)
  • 8 kHz 8-bit a-law encoded headerless (*.al)
  • 8 kHz 16-bit linear PCM WAV (*.wav)
  • 8 kHz 8-bit µ-law WAV (*.wav)
  • 8 kHz 8-bit a-law WAV (*.wav)
  • MP3 (*.mp3) - Note: If the audio file is poorly encoded, the mp3 will not work.

Prompt Queuing and Barge-in Behavior

Given a series of prompts to be queued and eventually played, all initial prompts that disallow barge-in will be treated as such. Once a prompt that allows barge-in is queued, all subsequent prompts will be queued for barge-in up to the point at which recognition triggers the playback of the queue. Prompt queuing, in fact, extends back beyond a given field's prompts, and will include all prompts in blocks declared immediately before the field.

Given a code snippet as follows:

  <prompt bargein="false">
    This is prompt one.
  <prompt bargein="true">
    This is prompt two.
<field type="digits">
  <prompt bargein="false">
    This is prompt three.
  <prompt bargein="true">
    This is prompt four.

“This is prompt one” would be queued and played immediately, and the user would not have the opportunity to barge in on the prompt. However, “This is prompt two”, “This is prompt three”, and “This is prompt four” would all be queued up together and played together, and the user would be able to barge in during any of the three prompts, including prompt three.