Compression of voice messaging can result in poor quality audio

Voice messages are normally stored in a compressed format. Although this reduces the storage requirements, it can cause problems if Unified Messaging is used in an environment that also uses audio compression, notably some Voice over IP infrastructures. Such use of multiple compression stages can result in the audio signal degrading, so that poor quality is experienced when listening to recorded messages.

Blueworx Voice Response and Unified Messaging Platform support the storage of voice messages in an uncompressed format. This facility can be used to maximize the quality of voice messages when they are used in an environment that employs its own compression mechanisms, for example a Voice over IP network using G.729A. The ability to use uncompressed messages is controlled using a Blueworx Voice Response system parameter called Voice Message Compression Type, which is in the Application Server Interface group . It can be set to compressed (default) or uncompressed.

Some points to note:
  1. Blueworx Voice Response must be restarted for a change in the value of Voice Message Compression Type to take effect.
  2. Compressed and uncompressed messages cannot be mixed on a Blueworx Voice Response system (either standalone or Single System Image), nor on multiple systems exchanging voice messages using Unified Messaging Internode Messaging.
  3. If you are not using Unified Messaging Platform, only change the Voice Message Compression Type system parameter when the voice database is empty.
  4. Incorrectly setting Voice Message Compression Type on an existing system prevents the playback of existing voice messages. Callers hear an error message and red alarms (error_id 20504) are displayed in the system console and in the error log.