Re: [vmeet] Audio echo
Douglas Otis <doug.mtview@gmail.com> Sat, 25 April 2009 03:20 UTC
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From: Douglas Otis <doug.mtview@gmail.com>
To: Henning Schulzrinne <hgs@cs.columbia.edu>
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References: <49F1FD36.4010208@bbiw.net> <A14D0D78-F418-430D-831C-96F4E132B062@gmail.com> <048201c9c520$99158700$cb409500$@net> <44C4C11A-1E22-4E63-B40F-4C074346119E@cs.columbia.edu>
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Date: Fri, 24 Apr 2009 20:21:39 -0700
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Cc: vMeet@ietf.org, 'Dave CROCKER' <dcrocker@bbiw.net>
Subject: Re: [vmeet] Audio echo
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On Fri, 2009-04-24 at 17:58 -0400, Henning Schulzrinne wrote: > > However, you only need these fancy boxes if you run full-duplex. If > you mute the floor microphones when the remote caller speaks (and vice > versa), i.e., in half-duplex mode, there can be no acoustic echo. This > is, I think, what Doug is proposing. This is more human effort, but a > whole lot simpler to install. Agreed. Even assuming the PA and the RMC were somehow closely integrated, depending upon the location of the remote speaker, the data-center offering the RMC services, and the location of the meeting, transmission line effects still introduce complex and unstable delays. In addition, acoustic echo canceling is never perfect even when all audio sources are fed through a common system. These system are expensive and difficult to configure when the goal is to allow both near and far sides an ability to talk freely. Dealing with acoustic residuals when both sides are talking represents a rather daunting problem. A manual half duplex mode ensures that those in the meeting room will be able to ensure good audio quality and its use at a very low cost. Also note that the suggested low cost BTC wireless keyboard has both volume and mute buttons to make the effort of controlling the Net-Box audio fairly minimal. Use of RDP protocols would eliminate passing around a keyboard, but this would be dependent upon the network. A wireless keyboard might be handy during network disruptions as it would enable a meeting to continue when the hotel router gets depressed. Slides for the meeting should also be stored in the Net-Box prior to the start of the meeting. While these devices also accept nearly any type of memory stick and contain system recovery images, it may be unwise from a security standpoint to rely on memory sticks being freely passed around. -Doug
- [vmeet] Comments on today's vMeet webex session Dave CROCKER
- Re: [vmeet] Comments on today's vMeet webex sessi… Doug Otis
- Re: [vmeet] Comments on today's vMeet webex sessi… Brian Rosen
- Re: [vmeet] Comments on today's vMeet webex sessi… Doug Otis
- Re: [vmeet] Audio echo Henning Schulzrinne
- [vmeet] Best Practices Fred Baker
- Re: [vmeet] Audio echo Douglas Otis
- Re: [vmeet] Comments on today's vMeet webex sessi… SM
- Re: [vmeet] Best Practices Doug Otis
- Re: [vmeet] Comments on today's vMeet webex sessi… Olivier MJ Crepin-Leblond
- Re: [vmeet] Comments on today's vMeet webex sessi… Eliot Lear
- [vmeet] Remote Visual Presentation for IETF Stock… Doug Otis