[wdmaudiodev] Re: WHQL for virtual audio driver

  • From: Matthew van Eerde <Matthew.van.Eerde@xxxxxxxxxxxxx>
  • To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Wed, 4 Nov 2015 02:05:27 +0000

I see.

Well, you can pass RoundTrip by following the instructions.

If you have a microphone endpoint, it will ask you to induce a sine tone on
that microphone endpoint.

For a physical mic, you would need a sine tone generator that you physically
placed next to the mic.

For a virtual mic that feeds from an application playing to some other
endpoint, you would need to find an application that generates a sine tone, and
point it at whatever playback endpoint feeds your virtual mic. For example, you
could use a YouTube video, or you could use the built-in sine generator wizard
in RoundTrip itself.

From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Arthur Chung (RDCT)
Sent: Tuesday, November 3, 2015 5:58 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: WHQL for virtual audio driver

Sorry for not making myself clear.
AP means user mode application as Tim said.

I've already made the audio pipeline working w/ the help of MSVAD and SYSVAD
My actual question is whether it could pass WHQL tests or not (for some tests
require physical connections).

The reason is I need to get Microsoft signature for silence installation
required by the user.
If I signed the driver myself, there will be a dialog asking something like "if
you trust the publisher..." (with a check box for "always trust").

從: wdmaudiodev-bounce@xxxxxxxxxxxxx<mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx>
[wdmaudiodev-bounce@xxxxxxxxxxxxx] 代表 Matthew van Eerde
寄件日期: 2015年11月4日 上午 01:52
至: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
主旨: [wdmaudiodev] Re: WHQL for virtual audio driver
I wasn’t sure whether Arthur meant “application”, “audio precision” (as a
colleague of mine suggested), or “access point” (e.g., perhaps the driver
functions as a Miracast receiver.) I’m still not sure, but like you I am
leaning toward “application”.

Arthur, can you confirm?

Tim, when you say a “pipe to user mode”, do you have in mind:

1. an audio playback endpoint that can be used by a dumb app (like
Virtual Audio Cable does it), or

2. a custom interface which the driver would expose to “in the know”
user-mode code?

The closest thing to audio routing that Windows supports today is the WASAPI
audio loopback interface. In principle a driver could be packaged with a
user-mode service which includes a WASAPI loopback client; this could deliver
the audio back to the driver via a custom mechanism, and the driver could do
whatever it liked with it (e.g., deliver it up on a recording endpoint.)

From: wdmaudiodev-bounce@xxxxxxxxxxxxx<mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx>
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts
Sent: Tuesday, November 3, 2015 9:40 AM
To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
Subject: [wdmaudiodev] Re: WHQL for virtual audio driver

Matthew van Eerde wrote:
OK, so this is an audio recording scenario.

You know, this is one of the more frequently requested scenarios in the audio
driver world. Has the Microsoft audio team given any thought to releasing a
simple skeleton virtual audio driver sample with a pipe to user mode? For
years we've had MSVAD, but that's a 20,000-line behemoth demonstrating a
thousand esoteric features that aren't germane to the simple non-hardware case.
And it was never obvious to the casual observer that CopyFrom and CopyTo were
the magic locations for tapping the audio streams. Now, we have SysVad, which
is even more complicated, and so far I haven't found where the magic tap
locations are.

That is - what is an “AP?”

That, in some parts of the world, is the accepted abbreviation for


Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>

Providenza & Boekelheide, Inc.

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