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cakeroyd
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Joined: June 13 2006
Location: United States
Posts: 2
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| Posted: June 13 2006 at 9:47am | IP Logged
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Does your SDK offer any echo cancellation features to help reduce acoustic echo and long echo?
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support
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Joined: January 26 2005
Location: United States
Posts: 1666
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| Posted: June 13 2006 at 10:57am | IP Logged
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Hi cakeroyd,
Thanks for the question. Echo cancellation can be a real pain for certain applications.
The VOIP Media Engine does not currently have integrated echo cancellation. We have developed an echo cancellation library that we sometimes use when developing applications for other OEM customers. Unfortunately we have not released this library as a standard product so it is not available to the public. I think we can handle echo cancellation up to approximately 120Ms. Larger echo cancellation algorithms can be computationally intensive beyond that and may not perform well on a generic PC.
Depending on the type of echo cancellation you must perform, it may be possible to find an echo cancellation library from open source or another vendor and use it with the Media Engine. The media engine allows you to access all media streams so applying an echo cancellation "block" somewhere would be a matter of developing the code to "hook it up".
We would be interested in knowing further what your specific application requirements are. Any info you can relay to us would be used to guide us in our echo cancellation implementation so we might is functionality to a future release. We will gladly work with you on this.
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cakeroyd
Intermediate
Joined: June 13 2006
Location: United States
Posts: 2
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| Posted: June 13 2006 at 11:12am | IP Logged
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Do you handle the 120ms echo cancellation through the private library or in the VoIP engine? Are you able to share the library or have plans to do so?
Thanks
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support
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Joined: January 26 2005
Location: United States
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| Posted: June 13 2006 at 12:04pm | IP Logged
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Hi cakeroyd,
You >>>
Do you handle the 120ms echo cancellation through the private library or in the VoIP engine?
<<< Support
When we have to, we handle echo cancellation using a LanScape developed private lib that is not currently part of the VOIP Media Engine.
You >>>
Are you able to share the library or have plans to do so?
<<< Support
No plans to offer a separate echo cancellation library. If enough customers want echo cancellation, we will make it part of the Media Engine.
Tell us a bit more about your current application and requirements and we might be able to help you identify a possible solution. We’d be glad assist you.
Repost as needed,
Support
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Jalal
Vetran
Joined: April 24 2006
Location: Iran
Posts: 188
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| Posted: July 10 2006 at 11:15am | IP Logged
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Do you know any Open Source or Commercial Echo Cancellation library that can be easily linked with LanScape VOIP Media Engine? If you know please list some of them.
Thanks
Jalal Abedinejad
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support
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Location: United States
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| Posted: July 11 2006 at 7:49am | IP Logged
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Hi Jalal,
We can't make any recommendations at this time. However, just about any good implementation of Normalized Least Mean Squared (NLMS) algorithm that can execute on a host PC using 20Ms PCM sample blocks can theoretically be used.
As far as open source may go, we performed a Google search and saw that the Open H323 project has something you might consider. Take a look at this link:
Acoustic echo cancellation - NLMS-pw algorithm
Or here:
Acoustic Echo cancellation memo
We continually work with customers to enhance and offer additional functionality in the VOIP Media Engine. So feel free to offer your suggestions and comment regarding the integration of echo cancellation into the media Engine.
Support
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support
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Location: United States
Posts: 1666
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| Posted: July 11 2006 at 8:35am | IP Logged
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Here is a link to Andre Adrian's work. His latest NLMS acoustic echo cancellation source code is there:
http://home.arcor.de/andreadrian/
Read the draft:
http://home.arcor.de/andreadrian/echo_cancel/draft-aec-03.tx t
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LanScape Support Forum -> LanScape VOIP Media Engine™ - Pre-Sales Technical Support
Topic: Acoustic Echo Cancellation (AEC)
