20 Voice API Programming Guide — June 2005
Product Description
1.6.1 Play and Record Functions
The voice library includes several functions and data structures for recording and playing audio
data. These allow you to digitize and store human voice; then retrieve, convert, and play this digital
information. In addition, you can pause a play currently in progress and resume that same play.
For more information about play and record features, see Chapter 8, “Recording and Playback”.
This chapter also includes information about voice encoding methods supported; see Section 8.5,
“Voice Encoding Methods”, on page89. For detailed information about play and record functions,
see the Voice API Library Reference.
1.6.2 Speed and Volume Control
The speed and volume control feature allows you to control the speed and volume of a message
being played on a channel, for example, by entering a DTMF tone.
Se Chapter9 , “Speed and Volume Control” for more information about this feature.
1.6.3 Transaction Record
The transaction record feature allows voice activity on two channels to be summed and stored in a
single file, or in a combination of files, devices, and memory. This feature is useful in call center
applications where it is necessary to archive a verbal transaction or record a live conversation.
See Chapter8, “Recordin g and Playback” for more information on the transaction record feature.
1.6.4 Silence Compressed Record
The silence compressed record (SCR) feature enables recording with silent pauses eliminated. This
results in smaller recorded files with no loss of intelligibility.
When the audio level is at or falls below the silence threshold for a minimum duration of time,
silence compressed record begins. If a short burst of noise (glitch) is detected, the compression
does not end unless the glitch is longer than a specified period of time.
See Chapter8, “Recordin g and Playback” for more information.
1.6.5 Streaming to Board
The streaming to board feature allows you to stream data to a network interface in real time. Unlike
the standard voice play feature (store and forward), data can be streamed in real time with little
delay as the amount of initial data required to start the stream is configurable. The streaming to
board feature is essential for applications such as text-to-speech, distributed prompt servers, and IP
gateways.
For more information about this feature, see Chapter 8, “Recording and Playback”.