Microsoft has a history of encapsulating shared audio functionality during major OS updates. The switch from Windows 95 to Windows 2000 introduced the WDM driver model. Most of the components that were part of a Windows 95 driver package were integrated into the OS for WDM, and a miniport driver was required for Logo. The same sort of shift took place in Windows Vista and Windows 7, where again most of the required functionality is provided by the UAA HD Audio class driver and the UAA USB Audio class driver.
These class drivers can be extended to provide all the customized audio functionality currently provided by Codec IHV’s custom audio function drivers. Not only does this approach provide a more economical approach, by reducing or eliminating kernel mode driver development, it provides OEMs with a codec-independent solution, so that audio feature development and hardware development can be decoupled.
When Microsoft introduced a new “Communications Device” category for Windows 7, they chose David Roach to introduce the hardware and software design concepts at WinHEC 2008. We can provide an overview of how OC devices integrate and coexist with existing high-fidelity audio design that is already supported in the Windows platform, along with insight into wideband telephony and the TIA-920 specification for measuring wideband telephony devices. Digital and analog microphones, beamforming microphone arrays, and USB & Bluetooth headsets are all part of the communications ecosystem. Identify the acoustical, electronic, and industrial design challenges in implementing communication devices and experience the benefits of "getting it right."
Driver packages which extend the class driver are similar to standard audio driver packages, but instead of containing an audio function driver, the INF file is used to reference the UAA class driver. Other components such as APOs and filter drivers are included as usual, and the entire completed package is tested and signed in the normal way. These packages can be posted to Windows Update or distributed directly by the OEM.
This approach leverages Microsoft’s driver development, and can dramatically reduce the effort required to provide a logoed audio driver package, while still supporting any custom features that might be needed for a specific model.
Design Services: Additional Design Architecture Support
22" x 17" wall chart from Intel Press that shows the complete audio signal flow diagram of both hardware and software in a modern PC.
Developing pin configurations is one of the critical new steps in the Windows audio development process. Optimal Sound will develop pin configurations and verb tables for your UAA-Compliant hardware. Deliverables include assembly-language verb tables for inclusion in the BIOS and .REG or .INF files containing temporary pin configuration settings. An optional audio flow diagram for each audio endpoint is available.
If your system is failing the audio fidelity logo tests, then adjustments to the layout are probably needed, followed by a re-spin of the motherboard. This is an expensive and time consuming process that should be avoided when possible. The best way to avoid re-spins is to design the audio circuitry properly in the first place. You can download David Roach's presentation at Microsoft's WinHEC 2005 in Seattle, discussing best practices for audio hardware design in a PC environment.
Optimal Sound provides technical documentation and graphics for all audio development services.
The book from Intel Press, High Definition Audio for the Digital Home: Proven Techniques for Getting It Right the First Time by David Roach, Scott Janus, and Wayne Jones is a good example of the work that Optimal Sound can provide. Audio Design Line has published an excerpt from the HD Audio book, by Intel Press, of Chapter 9 and an excerpt from Chapter 6 discussing clicks and pops.
Optimal Sound provides training in basic audio troubleshooting techniques , including how to determine whether an issue is HW or SW, and other ways to identify and resolve audio issues.
Use Optimal Sound to add an audio expert to your team, ensuring that your systems are easy to understand, functioning properly with Windows 7 and, of course, sounding great. Contact us for more info.