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Re: [codec] #14: VAD and CNG?

"Christian Hoene" <hoene@uni-tuebingen.de> Mon, 24 May 2010 16:00 UTC

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From: Christian Hoene <hoene@uni-tuebingen.de>
To: 'Brian Rosen' <br@brianrosen.net>, "'Olle E. Johansson'" <oej@edvina.net>
References: <B91793B7-9268-4105-9D17-D9A090ABB727@edvina.net> <C8201924.3582D%br@brianrosen.net>
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Date: Mon, 24 May 2010 18:00:13 +0200
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Cc: codec@ietf.org
Subject: Re: [codec] #14: VAD and CNG?
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Hi Brian,

I would say: This is a task of the phone to amplify the signal during an emergency call. Of course, the phone knows that a emergency
has been called and that any vague signal can be of importance. It should then switch over to a emergency mode (disabling
background-noise removals, changed automatic gain control, etc).

This requirement needs not be covered by signaling nor codec. The phone can take care of it much better.

Christian


>-----Original Message-----
>From: Brian Rosen [mailto:br@brianrosen.net]
>Sent: Monday, May 24, 2010 5:53 PM
>To: Olle E. Johansson
>Cc: codec@ietf.org; hoene@uni-tuebingen.de
>Subject: Re: [codec] #14: VAD and CNG?
>
>When you make an emergency call, background is a very important source of
>information.  For example, if the call taker hears someone threaten the
>caller, that will inform the response.  Often the caller is in distress, and
>may put the phone down, or speak faintly.  VAD will "zero out" the
>background sounds.
>
>Brian
>
>
>On 5/24/10 11:30 AM, "Olle E. Johansson" <oej@edvina.net> wrote:
>
>>
>> 24 maj 2010 kl. 16.48 skrev Brian Rosen:
>>
>>> I hope we are assuming VAD (or DTX) is negotiable.  It is essential (for
>>> emergency calls) that VAD is disabled.  While in many cases the endpoint
>>> will know that it is in an emergency call, and disable VAD, it is not always
>>> possible to know.
>>
>>
>> Just for curiosity, Brian. Why is it essential for emergency calls to disable
>> VAD?
>>
>> /O
>>
>>

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