[wdmaudiodev] Re: [EXTERNAL] APO with OutputDebugString

  • From: Joey Lag <itsjoeylag@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 20 May 2020 17:40:17 +0100

I am running Windows 10 Pro 64bit

On 20 May 2020, at 17:22, Matthew van Eerde (Redacted sender 
"Matthew.van.Eerde" for DMARC) <dmarc-noreply@xxxxxxxxxxxxx> wrote:

What version of Windows are you running in your VM?
 
From: wdmaudiodev-bounce@xxxxxxxxxxxxx <wdmaudiodev-bounce@xxxxxxxxxxxxx> on 
behalf of Joey Lag <itsjoeylag@xxxxxxxxx>
Sent: Wednesday, May 20, 2020 9:15:02 AM
To: wdmaudiodev@xxxxxxxxxxxxx <wdmaudiodev@xxxxxxxxxxxxx>
Subject: [EXTERNAL] [wdmaudiodev] APO with OutputDebugString
 
Greetings audio gurus!

I am reaching out to you as I am looking to incorporate a proprietary DSP 
algorithm within a windows driver. This is my first experience with windows 
driver development, and I have been doing some reading, in particular:
https://docs.microsoft.com/en-us/windows-hardware/drivers/kernel/introduction-to-wdm
 
<https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fwindows-hardware%2Fdrivers%2Fkernel%2Fintroduction-to-wdm&data=02%7C01%7CMatthew.van.Eerde%40microsoft.com%7C5364da9202a24215042808d7fcd90c97%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637255881501203911&sdata=vYXt6lyFpY3zETKvDl2m%2BQgXBSH1nMhtwTfeP1QdGtI%3D&reserved=0>
https://docs.microsoft.com/en-us/windows-hardware/drivers/audio/wdm-audio-architecture--basic-concepts
 
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https://docs.microsoft.com/en-gb/windows/win32/learnwin32/module-2--using-com-in-your-windows-program
 
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https://docs.microsoft.com/en-us/cpp/atl/active-template-library-atl-concepts?view=vs-2019
 
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From my reading, I have understood that software DSP is handled in ATL 
COM-based objects known as audio processing objects which exist in the 
user-mode Audio Engine which communicates with the drivers on the 
kernel-side. As a result I have begun editing the SYSVAD example project, in 
particular the Swap APO. The DSP algorithm runs on a proprietary software 
framework, and to test whether everything works correctly I have created an 
identical channel swap example with it and incorporated it within the MFX 
swap apo example. My testing setup uses a virtual box VM as the target, 
through which I use vmmon with windbg for debugging (Setup based on the steps 
at 
https://www.youtube.com/watch?v=XUlbYRFFYf0&list=PLZ4EgN7ZCzJx2DRXTRUXRrB2njWnx1kA2
 
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 Both host and target computers are 64-bit windows 10. 

I seem to be running into issues with this simple example - whenever I switch 
on the audio enhancements for the sysvad driver (which should apply the 
channel swap using our internal framework) a window pops up saying that 
“Windows has detected that audio enhancements for the following device are 
causing problems: [sysvad device name]. Audio enhancements for this device 
have been disabled. Would you like to reenable?”. As an initial step, I have 
included several “OutputDebugString” string calls to print some output to the 
debugger but this doesn’t seem to show through dbgview (run on target machine 
with administrator permissions with all capture types selected under capture 
menu). Any suggestions on what I have to do to see this output? I have also 
put in several OutputDebugString calls within the unaltered sysvad example 
and similarly I cannot obtain any debugging output. Also, I have added 
“DisableProtectedAudioDG” as a DWORD and set it to 1 in 
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Audio but this 
has not helped.

Many thanks guys. I understand that you’re all volunteering to help on this 
mailing list, so any clarifications are much appreciated!

- Joey

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