Background Noise Suppression; Comfort Noise Fill - Polycom SIP 3.1 Administrator's Manual

Algorithm MIME Type
Siren14 SIREN14/
16000
Siren22 SIREN22/
48000
RFC 2833 phone-event
Note
Central Configuration file:
sip.cfg
(boot server)
Local Web Server
(if enabled)

Background Noise Suppression

Comfort Noise Fill

Ref. Bit Rate
SIREN14 24 Kbps
32 Kbps
48 Kbps
SIREN22 32 Kbps
48 Kbps
64 Kbps
RFC 2833 N/A
The network bandwidth necessary to send the encoded voice is typically 5-10%
higher than the encoded bit rate due to packetization overhead. For example, a
G.722.1C call at 48kbps consumes 5xkbps of network bandwidth (one-way audio).
Two-way audio would take over 100kbps.
Configuration changes can performed centrally at the boot server or locally:
Specify codec priority, preferred payload sizes, and jitter buffer tuning
parameters.
• For more information, refer to
on page
Specify codec priority, preferred payload sizes, and jitter buffer tuning
parameters.
Navigate to http://<phoneIPAddress>/coreConf.htm#au
Changes are saved to local flash and backed up to <Ethernet
address>-phone.cfg on the boot server. Changes will permanently
override global settings unless deleted through the Reset Local
Config menu selection and the <Ethernet address>-phone.cfg is
removed from the boot server.
Background noise suppression (BNS) is designed primarily for hands-free
operation and reduces background noise to enhance communication in noisy
environments.
There are no related configuration changes.
Comfort noise fill is designed to help provide a consistent noise level to the
remote user of a hands-free call. Fluctuations in perceived background noise
levels are an undesirable side effect of the non-linear component of most AEC
Sample
Rate Frame Size
32 Ksps 20ms - 80ms
32 Ksps 20ms - 80ms
N/A N/A
Codec Preferences <codecPref/>
A-38 and Codec Profiles <audioProfile/>
Configuring Your System
Effective
audio
bandwidth
14 KHz
14 KHz
N/A
on page A-41.
4 - 77