Hi all,
I am new to WDM and DSHOW.

I had downlad a VVD(Virtual video device) DSHOW filter from TMH's
website and it worked.

Now I want to implement a virtual audio device(VAD) DSHOW filter, the
first thing I tried was to modify the VVD source code, I changed all
the video type settings to audio type to form my VAD.
And then it could be added to GraphEdit and I could hear
voice...
But I want to implement it on the MSN to share the audio
streaming with my friends.
I had did some researches including googling the websites...

(a)
From the MSDN, I found:
============================================================
Audio Capture Filter

The Audio Capture filter represents an audio capture device. It has
one capture output pin and several input pins (one for each type of
input on the card, such as LineIn, Mic, CD, and MIDI).

On Wed, 26 Mar 2008 01:34:17 -0700 (PDT), Joseph wrote:

As far as I know MSN doesn't use DirectShow for audio capture so writing a
source filter won't work like it did for the video.

You can write a driver level VAD that will work with DirectSound and
DirectShow. It's considerably more complicated but there is a sample in
the Windows DDK (current version is Server 2008) \src\audio\msvad\

Thanks, Chris P.

I have 2 questions.

(1)
The first one:
As the bellow website mentioned
http://pollos-blog.blogspot.com/2007/05/testcap-audio-capture-pin-windows.html

In the lowermost diagram...
the article showed 3 conditions to let SysAudio.sys to recognize a
Audio Capture Device:
1. has a Analog Audio Input Pin
2. has a Audio Output Pin
3. there must at least one node between these two pins

Is the SysAudio.sys driver-related?
If it is DSHOW-related, I want to ask the question two.

On Thu, 27 Mar 2008 18:49:41 -0700 (PDT), Joseph wrote:

SysAudio.sys encapsulates the WDM audio drivers. You still have to write a
driver, you cannot do it with DirectShow in this case.