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What is Audio Architecture of Windows 7

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Novice here on Audio Architecture, especially WASAPI and Kernel

Streaming. Wikipaedia claims KMixer was removed in Windows

Vista, is this the same for Windows 7? Do you still need Kernel

Streaming Plug-in for Media Player? How do you bypass the Windows Volume Control in Windows 7? Still need Plug-in? Is this Volume Control in Windows 7, in the Digital or Analog Domain. If in Digital, how do you Bypass? How does this effect

USB Digital Out to Stereo System, is Volume Control still in the loop? Do you still need to Plug-in WASAPI in Media Player

with Windows 7 System? There are Speaker Properties in Windows 7, are they a function of the Sound Card and isolated from the

USB Digital Output? These Functions include Enhancements like

Bass Boost, Virtual Surround, Room Correction, and Loudness

Equalization. Other Functions include Level Control. Advanced

Functions include Default Format-select the Sample Rate and Bit

Depth to be used when running in SHARED MODE. Other Functions

like EXCLUSIVE MODE-allow Applications to take exclusive control of this Device, and give EXCLUSIVE MODE Applications

priority. Are these Functions bypassed when using USB Digital

Out to Stereo System DAC? SHARED MODE and EXCLUSIVE MODE sound

alot like WASAPI MODES to me, or am I wrong? If you replace

Windows Media Player 12 with another Media Player, J. River Media Center, Foobar 2000, or Winamp in Windows 7-still going

to need WASAPI and Kernel Streaming Plug-ins with Windows 7?

I can't seem to find any information about the Audio Architecture of Windows 7.


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Hi there,


Far too many questions, but here is the most important on the W7 audio architecture (hence sure not answering all your questions) :


There is as much "mixer" in W7 as there was from off XP, and actually worse, because in XP we could shut it off by various means. Not so in (Vista and) W7. BUT, in Vista/W7 there is WASAPI/Exclusive, and this means that a program can use the audio device exclusively *that* implying that no "mixing" (mind that word) needs to be involved - and thus isn't. This is "Exclusive Mode" only. So, WASAPI Shared Mode doesn't help a thing here, and there it's just another means of stuffing audio through a pipe.

From off Vista KMixer is called "Audio Engine".


The "priority" you talk about goes along with the new audio stack since Vista (MMCSS) and is by itself not WASAPI related. However, it is not quite working as MS promises, and in the end that's so "bad" that in W7 it has been removed again. Ok, not "removed" as such, but not giving that priority anymore as it can in Vista.


Besides WASAPI there's also Kernel Streaming for exclusive use of the audio device, and that too avoids the mixer (read : is bit perfect). Officially *this* isn't there anymore since Vista, but it's just an MS commercial to get WASAPI going. It just is there, up to today in W7.


Of course there's also ASIO to avoid the mixer, but this is completely separate from Windows itself.


If you replace Windows Media Player 12 with another Media Player, J. River Media Center, Foobar 2000, or Winamp in Windows 7-still going to need WASAPI and Kernel Streaming Plug-ins with Windows 7?


Probably your most important question, but sadly I don't understand it. Maybe it helps you if I tell that WMP was about the last one using WASAPI and is all but leading here.

WASAPI is an audio driver (means) and a program like Foobar may use it. Also, it is not related to "plugins" as such, which is just a means of "structured programming" and use software which was written outside of the program where it can be used. For example, I myself (XXHighEnd) don't use any plugin for it at all, but you can bet that's because I was the very first with WASAPI and nothing existed for it back then (end of 2006).

So, if I understand your question correctly - if you want to use WASAPI, you just need a player which supports it, by means of plugins or directly.


I don't see separate "procedures" for USB, although I'll admit that usually it is cumbersome (if not impossible) to check for an USB DAC to be 100% bit perfect at all times over USB. But this was XP (and the mixer yes/no involved); Use WASAPI/Exclusive (or KS or ASIO) and it *will* be.


Lastly, using WASAPI as such doesn't imply bit perfectness (hence avoidance of the mixer) at all, and for some players it will be guessing. This is because they can use Shared Mode just the same, and you may not know. E.g. Foobar uses Exclusive Mode only, as does XXHighEnd.


I hope this helps you on the track a bit.









Lush^3-e      Lush^2      Blaxius^2.5      Ethernet^3     HDMI^2     XLR^2

XXHighEnd (developer)

Phasure NOS1 24/768 Async USB DAC (manufacturer)

Phasure Mach III Audio PC with Linear PSU (manufacturer)

Orelino & Orelo MKII Speakers (designer/supplier)

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Thanks PeterSt: I am still struggling to understand this

Computer Audio. Whole new Universe! I type in WASAPI, SHARED

MODE, EXCLUSIVE MODE in Help and Support Window of Windows 7.

I get nothing! Do these options come up when installing a New

Media Player? It sounds like different Media Players tap into

either Shared or Exclusive Mode, it doesn't sound like something that I can control. Everyone says get a Media Player

that is compatable with WASAPI. Do I presume Windows Media

Player 12 is compatable? How do you switch between Shared and Exclusive Modes with Windows Media Player 12?

The Priority I refer to, is a function of the Speakers

Properties Tool, in the bottom Tool Bar of Windows 7. It has a little Speaker with sound waves coming out of it. Left Click it, and then Left Click Speakers(High Definition Audio Device). You end up with a Window with Tabs for General, Level, Enhancements, and Advanced. These seem to be functions of the 3.5 mm Audio Outputs and the Sound Card, or am I wrong? Are these Functions Bypassed when using USB Output to USB DAC?

If I understand you correctly, WASAPI is an Audio Driver (means) that already exists in Windows 7, and you need a Media Player that is compatable with it. Still don't know how to switch between Exclusive and Shared Modes. Exclusive Mode is desirable since there is less or no mixing.

I don't quite understand if KMixer is still there in Windows 7. You say it isn't there, but Windows 7 utilizes other means of mixing. Does Windows 7 utilize Kernel Streaming? How do you utilize it? Is Kernel Streaming even

helpful if plugged into Windows 7? If you use a different Media Player other than Windows Media Player 12, is a Kernel

Streaming Plug-in even helpful with Windows 7, or is it a


My last question concerns Multi-Channel Advanced Resolution Surround Sound 24/96 Recordings. Pioneer DV-58AV can Downmix these to 2 channels, the Sound of these is stunning. DVD Audio Extractor can transfer this to Hard Drive. Apparently, the Multi-Channels are compressed into 2 on the Disk, via Meridian Lossless Packing. DVD Audio Extractor can Downmix Multi-Channel to 2 Channels in the Digital Domain. Any of this Exclusive Mode, Kernel Streaming, mixing avoidance affect the ability to Downmix Multi-Channel? Does it affect the ability to Upsample or Downsample?

Thanks for your patience, I appreciate it!


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The Help and Support pages for Windows 7 are intended to assist end users of the OS. The questions you're asking are related to programmers developing applications. For these sorts of questions, you should go to MSDN. A good starting point would be the User-Mode Audio Components page at http://msdn.microsoft.com/en-us/library/dd316780(v=VS.85).aspx.


A description of Exclusive Mode may be found here - http://msdn.microsoft.com/en-us/library/dd370844(VS.85).aspx.


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