Comfort Noise Generation Seed Parameter on Conferencing Media Loads
Symptom:
For Dialogic® System Release Software versions 5.1.1 FP1 to 6.0 PCI, conferencing algorithm changes were made to improve the audio quality of conferences. For some users, the default volume of the comfort noise may be too loud and may be audible as a 'hiss' when someone stops speaking.
The default Comfort Noise Generation seed value for volume is now modifiable via .config file. This value allows you to adjust the volume of the generated comfort noise that is introduced by the NLP component.
Reason for the issue:
The NLP component is used to detect echo returning to the conference and overwrites echo with a white noise pattern that may be perceived as too loud by users.
Solution:
This new parameter allows the user to adjust the initial volume of the generated comfort noise. In conferencing situations where users report hearing trailing static after the voice, this indicates that the parameter may need to be adjusted.
The parameter number is 0x2c22 and the default value is 0x4285fc. To lower the volume of the comfort noise generated, change this parameter’s value to 0xfff
After the changes are made, the parameter section in the .config file looks like this:
[0x2c]
SetParm=0x2c22,0xfff
Another possible value that may be tested is 0x0. The value of 0xfff may still result in some noise, and zero has been observed to provide a preferable result in some cases.
After adding this parameter to the .config file, you will need to run FCDGen, then re-start the Dialogic Services.
Product List
This parameter is only available on Dialogic® DM3 Media Boards after Dialogic® System Release Software 6.0 PCI SU build 8.
This parameter is supported on all Dialogic® Host Media Processing (HMP) Software 3.0 and later versions.
This parameter is supported on all DM3 Media Boards that support conferencing, including but not limited to:
Dialogic® DM/V480A-2T1-PCI Media Board
Dialogic® DM/V600A-2E1-PCI Media Board
Dialogic® DM/V960-4T1-PCI Media Board
Dialogic® DM/V1200-4E1-PCI Media Board
Dialogic® DM/V600-TEP-PCI Media Board
Dialogic® DM/V1200B-TEP-PCI Media Board
Glossary of Acronyms / Terms
NLP - Non-Linear Processor - a component used for echo cancellation.
Related Documentation
First published: 20-Apr-2009
Last published: 30-Sep-2011
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