Universal Audio Architecture

Universal Audio Architecture (UAA) is an initiative unveiled in 2002 by Microsoft to standardize the hardware and class driver architecture for audio devices in modern Microsoft Windows operating systems. Three classes of audio devices are supported by default: USB, IEEE 1394 (Firewire), and Intel High Definition Audio, which supports PCI and PCI Express.

Starting with Windows Vista, Microsoft requires all computer and audio device manufacturers to support Universal Audio Architecture in order to pass Windows Logo.

Overview

The goal of the Universal Audio Architecture is to solve a very common problem in modern Microsoft Windows products, that of inconsistent support for audio. Due to the lack of a common system by which audio devices could describe their capabilities to the operating system, not to mention a lack of ability to control those capabilities, audio device manufacturers (such as Creative Labs, Realtek, Turtle Beach and others) have had to provide a series of control panels and custom interfaces to let a user control the device. This, in turn, requires kernel-mode drivers so that the user's actions can be communicated to the hardware itself. Poorly-written audio drivers have been a common source of system instability in Windows, especially with games that make use of extended audio card capabilities. These concerns prompted Microsoft to disable the audio stack entirely by default in Windows Server 2003.

UAA seeks to resolve problems by putting forth a standardized interface which audio devices can follow, ensuring that the device's capabilities will be recognized and used effectively by Windows, without the need for additional drivers or custom control panels. It also provides a reasonable assurance that an audio device will still be able to work many years down the road, without requiring vendor-supplied drivers for a newer version of Windows.

Meanwhile, some alternative technologies were designed by third parties to achieve special qualities, which WDM lacked. For example, ASIO (by Steinberg) was created to achieve low latency and stays supreme compared to UAA. New systems that implement UAA policy (such as Windows Vista) are rejected by some audio engineers, because of no legacy software compatibility.

Another goal of UAA is to provide better support for multi-channel audio in Windows so that, for example, multi-channel WMA Pro audio streams can be played without special driver support.

UAA is intended to be a complete replacement for developing WDM Audio Drivers; however, in some cases it may be necessary for an otherwise UAA-compliant audio device to expose capabilities that cannot be done through UAA. Windows will continue to fully support audio drivers that use the PortCls and AVStream drivers. [http://www.microsoft.com/whdc/device/audio/wdmaud-drv.mspx Getting Started with WDM Audio Drivers] provides further information on when it is appropriate to develop a custom audio driver.]

History

In 2004, Microsoft provided the first version of UAA as an update to Windows 2000 Service Pack 4, Windows XP Service Pack 1 and Windows Server 2003, but is only available by contacting Microsoft support directly. [http://support.microsoft.com/kb/835221/ MSKB 835221] describes the initial driver release, and [http://support.microsoft.com/kb/888111/ MKSB 888111] describes the 1.0a update.] However, almost all manufacturer supplied drivers contain the UAA class driver. Windows XP Service Pack 3 also includes the updated driver.

In Windows Vista, the Windows Logo program requirements state that any machine shipped with Vista must include a UAA-compliant audio device that works without additional drivers.

Notes and references

Service pack 3 final release does not contain UAA.Machines upgraded from SP2 are OK and retain UAA.A number of vendors hardware refuses to install on XP SP3 because the drivers ship with the existing hotfixes (that refuse to install on SP3).No UAA fix for SP3 is available from MS at the moment but some unofficial re workings of the SP2 driver that allow it to work on SP3 exist. Existing Hotfixes (excluding XP SP3 31/7/08) http://support.microsoft.com/kb/888111Missing UAA report http://forums.microsoft.com/technet/showpost.aspx?postid=2721330&siteid=17&sb=0&d=1&at=7&ft=11&tf=0&pageid=1MS say it is in SP3 http://support.microsoft.com/kb/946480/

External links

* [http://www.microsoft.com/whdc/device/audio/default.mspx Audio Device Technologies for Windows] — Windows Hardware Developer Center web site
* [http://www-307.ibm.com/pc/support/site.wss/document.do?sitestyle=lenovo&lndocid=MIGR-65440 Universal Audio Architecture (UAA) High Definition Audio class driver (Q888111) for Windows XP with Service Pack 1]

See also

* Windows Vista audio architecture
* Windows legacy audio components