[wdmaudiodev] Re: - How to capture HDMI audio output data? Whether is sAPO a choice for it?

  • From: Jun Jiang <jun.jiang77@xxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Fri, 21 Oct 2011 04:54:07 +0000

Hi Tim,  Thank you very much. Yes, the latency is a question. Now I need to 
find a way to capture HDMI audio output data firstly and check latency 
later.For my case, I use a 3rd part application and this application can trun 
off Microsoft AEC.Actually, I want to find a way to disable Microsoft AEC, such 
as set key in Register. But I does not find it now.  Could somebody show 
suggetion on it? Could you please check my following questions about APO?Thanks 
in advnace. I found your previous post, 
http://www.winvistatips.com/system-wide-audio-filter-driver-t819251.html, about 
APO.You said that APO is the extension of hardware and it should co-work with 
hardware together.I just want to know if it is possible to make a APO to attach 
to other hardware driver, such as my case, to attcah to Intel Display Audio 
driver to capture output audio data? Or to attach to some system level to 
capture audio output data?Or whether can I make the global APO to capture all 
possible audio output data
 ?  My another question: Is APO not recommended to do it or APO impossible to 
do it?   Many thanks,Audleyswood

 Date: Thu, 20 Oct 2011 14:19:56 -0700
From: timr@xxxxxxxxx
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: - How to capture HDMI audio output data? Whether is 
sAPO a choice for it?


    Jun Jiang wrote:

        My question: How to capture HDMI audio output data? Whether is
        sAPO a choice for it?


        I need the speaker data to do AEC. 

        In my Windows 7 x64 PC, the audio output data was sent to HDMI
        speaker. The HDMI audio driver is Intel Display Audio driver. 

        Whether is sAPO a choice to capture HDMI audio data? Here, I can
        not change anying about HDMI audio driver because it is Intel
        driver not ours.

        I am newie on sAPO.  Could somebody show me suggestions? 


        If sAPO is not good choice to capture HDMI audio data, How can I
        do? Is there anohter way to do it?


    What you're asking is not easy.   You can use a user-mode
    application to hook into the loopback feature of the audio renderer
    to get that data, but you still need to have a place to feed that
    back in to your AEC algorithm, and you need rather precise latency
    information as well.


    One of the unfortunate things is that Microsoft already has an AEC
    solution.  It's clear there are a number of companies who have
    invested many years of research into AEC algorithms, who do not
    trust the Microsoft code.  If there were a nice plug-in interface to
    replace the core algorithms but leave the plumbing in place, it
    would be a great tool.

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

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