Background Noise Suppression - Polycom IP 320 Administrator's Manual

Algorithm MIME Type
Lin16 L16/8000
L16/16000
L16/32000
L16/44100
L16/48000
Siren14 SIREN14/
16000
Siren22 SIREN22/
48000
RFC 2833 phone-event
iLBC iLBC
Note
Central Configuration file:
sip.cfg
(provisioning
server)
Local Web Server
(if enabled)

Background Noise Suppression

Ref. Bit Rate
RFC 1890 128 Kbps
256 Kbps
512 Kbps
705.6 Kbps
768 Kbps
SIREN14 24 Kbps
32 Kbps
48 Kbps
SIREN22 32 Kbps
48 Kbps
64 Kbps
RFC 2833 N/A
RFC 3951 13.33Kbps
15.2Kbps
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 about 100kbps of network bandwidth (two-way
audio).
Configuration changes can be performed centrally at the provisioning 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 provisioning server. Changes will
permanently override global settings unless deleted through the
Reset Local Config menu selection.
Background noise suppression (BNS) is designed primarily for hands-free
operation and reduces background noise to enhance communication in noisy
environments.
Sample
Rate Frame Size
8 Ksps 10ms
16 Ksps
32 Ksps
44.1 Ksps
48 Ksps
32 Ksps 20ms - 80ms
48 Ksps 20ms - 80ms
N/A N/A
8 Ksps 30ms - 60ms
20ms - 80ms
Codec Preferences <codecPref/>
A-45 and Codec Profiles <audioProfile/>
Configuring Your System
Effective
audio
bandwidth
3.5 KHz
7 KHz
14 KHz
20 KHz
22 KHz
14 KHz
22 KHz
N/A
3.5KHz
on page A-49.
4 - 81