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Re: Echo cancellation

From: Stefan Hakansson LK <stefan.lk.hakansson@ericsson.com>
Date: Thu, 8 Dec 2011 12:02:26 +0100
Message-ID: <4EE09942.5040303@ericsson.com>
To: public-webrtc@w3.org
On 12/08/2011 11:55 AM, Dominique Hazael-Massieux wrote:
> Le jeudi 08 décembre 2011 à 11:41 +0100, Dominique Hazael-Massieux a
> écrit :
>> * echo cancellation (F9) was specifically discussed during the F2F; the
>> current requirement asks whether this is something that needs to be
>> dealt only at the browser level, or also at the Web app level. If the
>> latter came out to be needed as well, then that would raise the need for
>> the Audio API. I'll start a new thread on that topic.
> So, the current requirement documents leaves the question open as to
> whether the Web application needs to have control over echo
> cancellation.
>     F9              When there are both incoming and outgoing audio
>                     streams, echo cancellation MUST be made available to
>                     avoid disturbing echo during conversation.
>                     QUESTION: How much control should be left to the
>                     web application?
> Reading through the use cases, none of them seems to suggest a case
> where the Web app needs to have specific control on echo cancellation.
> Can anyone think of a reason why it should? Shouldn't this be something
> that "just" happens whenever audio streams are exchanged? or should it
> only happen for some audio streams?
My default view is the same (i.e. just happens). But this has not really 
been discussed, and there can be reasons for giving control:
* The echo canceller introduces a lot of clipping (or other artefacts), 
and there is no need since the user uses a head set
* The echo canceller consumes a lot of CPU (and is not needed)
It can be noted that if you go into "settings" of many commercial 
clients today you get the option to disable the EC
> I'm not clear if there is anything that we need from the Audio WG on
> this bit, if it is all to be handled on the browser side. We may need to
> have a flag on audio tracks to enable/disable echo cancellation (if
> there are indeed use cases for that), but I don't think we should expect
> each Web app to manually use the audio API to do echo cancellation.
> Thoughts?
> Dom
Received on Thursday, 8 December 2011 11:02:51 UTC

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