[wdmaudiodev] Re: AEC in Vista

  • From: Chao He <chaohe@xxxxxxxxxxxxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Wed, 4 Oct 2006 13:23:00 -0700

Reply bounced back. Resend.


People have been debating on where AEC should go for a long time. The
advantage of doing AEC inside audio API is exactly what you mentioned -
everyone gets it without additional programming. But doing AEC in
application level also has advantages. For example, application can
easily get full control over it and developers can improve/update it
easily. I think one important reason for Vista to do AEC in application
level is AEC on PC is still evolving in a very fast pace. Many AEC
customers would like to do additional programming work if they can get
AEC quality improved. As a matter of fact, both MSN messenger and SKYPE
are using AEC in application level in XP even though XP provides AEC
functionality (aec.sys) via DSound.


Chao He

Microsoft Corporation



From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts
Sent: Wednesday, October 04, 2006 10:20 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: AEC in Vista


Shuba Iyer wrote: 


AEC and microphone array processing in Vista are application graph
features. So it is up to the application to use the feature or not.

You know, the more I think about this statement, the more I think this
position is completely wrong.

AEC is perhaps "the" canonical feature that one would want to use
globally.  As a user, I'm not going to think about AEC as an application
add-on.  Instead, I'm going to think about AEC as an attribute of the
microphone array.  If I have installed some kind of AEC, then I want
echo cancellation in every application that uses that microphone,
whether it be wave, DSound, or WASAPI.

I've been using Sound Recorder as an example, but that's the wrong
example.  With the policy you have described, there is no way to use an
AEC-enabled microphone with NetMeeting, which is one of the apps where I
would most want echo cancellation.  In fact, if I am a vendor supplying
my own AEC DMO following your model, there is no way to have it get used
by any applications other than the ones I have written myself.

That ain't right.  Have I misunderstood your position?

Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.

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