[wdmaudiodev] Re: GFX/LFX fullduplex support.

  • From: Tim Roberts <timr@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Thu, 04 Sep 2008 12:03:06 -0700

pete c wrote:
> In regards to the following statement below:
> >> Of course, you are going to NEED such synchronization if you hope to do
> >> echo cancellation.  That's another thing that makes this tricky.  You
> >> will need some pretty brainy algorithm scientists to make this work.
> I know that i need GFX/LFX synchronization for AEC to work, however im
> not convinced that it may even be possible,  since the GFX is
> independent (speaker driver) process from the LFX (microphone driver)
> process. Is it possible to synchronize these two independent processes
> with each other within Vista and if so what type of mechanism would be
> recommended?

The "recommended" approach is not to do this at all, and instead rely on
the DMO approach.  ;)

You know the output sample rate.  You know the input sample rate.  Yes,
they drift, but you can detect that.  You will be getting blocks at
regular (short) intervals, so you can detect changes in timing over
time.  It's not easy, but I told you that already.

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

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