Also, make sure to implement
IAudioSystemEffects2::GetEffectsList<https://msdn.microsoft.com/en-us/library/windows/desktop/dn280325(v=vs.85).aspx>
and report AUDIO_EFFECT_TYPE_VIRTUAL_SURROUND,
AUDIO_EFFECT_TYPE_VIRTUAL_HEADPHONES, and/or other effects types as appropriate
so that apps are aware of the processing you're doing.
From: Edward Abramian<mailto:edwabr123@xxxxxxxxx>
Sent: Friday, December 2, 2016 1:39 PM
To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
Subject: [wdmaudiodev] Re: Multichannel audio USB support
Thank you for clarifying this for me. I will try you recommendations.
Have a great weekend!
Edward
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Matthew van Eerde ;
(Redacted sender "Matthew.van.Eerde" for DMARC)
Sent: Friday, December 2, 2016 1:33 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Multichannel audio USB support
I see, you want to provide custom downmixing.
You can do this by implementing an SFX APO that supports both stereo and
multichannel input, and always outputs stereo. Your driver package will have an
.inf and a .dll in it; no need for a custom .sys.
Media players will call IAudioClient::IsFormatSupported(...) with the source
content. If the source is multichannel, this will succeed, and your custom
downmixing will be in effect.
(To be complete, I will mention that whether IAudioClient::IsFormatSupported is
called depends on the particular API the app is using to stream. Some legacy
APIs will open in the mix format regardless of the source content. For those
apps, your SFX will be opened in stereo mode.)
From: Edward Abramian<mailto:edwabr123@xxxxxxxxx>
Sent: Friday, December 2, 2016 1:27 PM
To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
Subject: [wdmaudiodev] Re: Multichannel audio USB support
The resulting audio device will support multichannel input through downmixing
it into stereo in SFX. The downmixing is done the way it preserves sound
localization by use of binaural/HRTF techniques. So apps are free to choose
multichannel output on that device.
From: wdmaudiodev-bounce@xxxxxxxxxxxxx<mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx>
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts
Sent: Friday, December 2, 2016 1:22 PM
To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx>
Subject: [wdmaudiodev] Re: Multichannel audio USB support
Edward Abramian wrote:
To be clear on what exactly I need, let me describe it from the user
perspective. I want a USB audio device to show up as supporting multichannel
input, such as 5.1 or 7.1, so that user can configure it from Speaker Setup
control panel. Internally, per my understanding, this will mean downmixing
multichannel input into stereo in SFX to match USB headset stereo output.
If the hardware does not support 5.1 or 7.1, why would you want to pretend that
it does? That's just going to produce a confusing user experience. Apps will
assume they can exploit the additional channels.
--
Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
Providenza & Boekelheide, Inc.
