Vista Audio System Development Steps

The new audio logo requirements for Vista have introduced a number of new steps in the audio subsystem development process. The list below uses a red bullet on the left to identify development steps that are new to Vista. The legend shows that a green icon indicates steps that Optimal Sound can fully or partially outsource for you, while the purple icon indicates steps that Optimal Sound can assist and/or advise on. The steps indicated by the gold icon are typically performed by the system vendor and the motherboard development team. Click on the description for more details on each item.

These steps assume that the audio device is already logoed and has passed all audio fidelity tests included in the audio device category.

---

Determine System Classification

The first step in audio design for Windows Vista is determining the system classification. The audio requirements vary depending on whether the system is intended for consumer or commercial applications, on whether it is a laptop or a desktop, and whether the system is targeting premium logo or standard logo for Vista.

Determine Audio Feature Set

The next step is to determine the audio feature set. For Vista systems, special attention should be paid to UAA compliance and class-driver compatibility. Many features considered standard for AC97 are no longer supported in Vista. For instance, analog signals passing through the codec are not supported under the Vista mixer model, nor is analog CD playback standard. If both XP and Vista implementations are needed for the same system, these should be considered separately for the most part. Driver and installer packages will likely be kept separate for XP and Vista.

Select Codec and Chipset Vendors

Once you know the system audio architecture, then you can start selecting the audio hardware. The HD Audio controllers included in all popular southbridge chipsets are roughly equivalent. Audio is usually not a consideration in the selection of the southbridge chipset, as long as HD Audio is implemented properly. The codec selection is more complex. At a minimum, the selected codec must support all the audio paths defined in the system audio architecture. Codec vendors often offer differentiation via their software offerings, since the competing codecs are fairly similar to each other. Pay careful attention to any higher-than-normal fidelity requirements for the system, as well as non-standard inputs and outputs that are not UAA compliant.

(Optional) Generate Audio Flow Block Diagrams

The best way to understand complex usability scenarios is to generate audio signal flow diagrams for the primary use cases for each system. Having a flow chart to refer to can streamline communication between audio team members and help the team focus on a common goal. Optimal Sound can create audio flow charts for you. Click here for more info.

(Optional) Determine Audio Architecture for 3rd Party APOs

Determine whether to augment Microsoft's built-in Audio System Effects with additional processing modules from codec vendors or APO vendors. In order to qualify for the premium Vista logo, you must rewrite or replace previous Windows XP audio implementations that perform audio signal processing within the kernel mode audio driver.

(Optional) Determine if 3rd Party WaveRT driver is needed

With signal processing moved to the sAPO and the availability of the HD Audio UAA class driver, you should carefully evaluate whether a custom WaveRT driver is needed for your system. Unless you need custom functions such as jack retasking or microphone array support, you should be able to minimize test and support costs by using the UAA HD Audio class driver as the primary audio driver for your system.

Generate Audio Schematics

Now it's time to generate the schematics of the audio circuits on the motherboard. Each audio endpoint in the system should be evaluated for UAA compliance during this design stage. Any special circuitry must be designed to work properly with the UAA HD Audio class driver. For instance, if a GPIO is used to mute an output, then GPIO must default to the unmuted configuration when the class driver is loaded.

Generate Layout and Gerber Files

The schematics are then used to generate the circuit board layout file, known as the gerber file. This is an important step for the audio fidelity, since a poor layout can cause the audio fidelity logo tests to fail. Unlike in the past, each motherboard design must pass audio fidelity tests on its own.

(Optional) Develop 3rd Party APOs

If 3rd party APOs are being used for the design, they must be developed or customized for your system. This step is not necessary if only the built-in Audio System Effects are used, or if the APO is already fully developed and ready to go.

(Optional) Develop 3rd Party WaveRT Driver

Likewise, it may be necessary to perform additional development on the WaveRT driver to meet specific system requirements. Systems that use the UAA HD Audio class driver can omit this step.

Manufacture Motherboard

The system vendor will then build and stuff the first motherboard prototype. This process takes 2 to 4 weeks under normal circumstances.

Generate Pin Configuration Verb Tables

Once the system architecture and the schematic design are completed, then the pin configuration verb tables can be generated. These tables describe the position and color of each jack on the system, and provides the OS with information on what to display on the screen. The pin configuration verb tables can be validated using a manual procedure documented by Microsoft here.

Integrate Verb Tables into BIOS

The pin configuration tables are then integrated into the BIOS. Because this is a new step in the process, it can often take as much as two or three weeks between the time that the updated verb tables are submitted and when a BIOS containing this table becomes available. While it's possible to use the registry or an INF file to override incorrect verb tables during development, these settings are not capable of passing logo testing. The BIOS must contain properly configured pin configuration verb tables in order to pass the logo tests.

Bring up motherboard with UAA HD Audio class driver

You should use the UAA HD Audio class driver for initial audio system bringup. If you've done your job properly, then the BIOS already contains the proper pin configuration verb tables and the audio class driver is installed automatically when Windows is installed.

Run System Pin Configuration Logo Test using UAA Class Driver

Run the UAA logo tests to check the pin configuration on the motherboard. If this test is failing, or if the UAA HD Audio class driver is causing a Code 10 error, then the verb tables are incorrect. You must correct the tables and re-integrate into the BIOS before testing can proceed further.

Run Audio Device and System Audio Fidelity Logo tests using UAA Class Driver

Once the pin configuration tests are passing, you should run the audio fidelity logo tests next to verify that the motherboard schematics and layout design are capable of passing the logo tests. For systems, even though these tests are not required to pass until June 1, 2007, the test logs must be included with every Vista logo submission. Microsoft allows system vendors the option of running the fidelity tests themselves or contracting them out to an independent test facility.

Optimal Sound provides training in how to configure DTM for the audio fidelity tests, and it also offers an independent audio fidelity logo testing service. If these audio fidelity logo tests are failing, Optimal Sound provides troubleshooting services to identify the issue and recommend timely and cost effective solutions.

Run all other Audio Device and System Audio Logo tests using UAA Class Driver

Once you have run the new pin configuration and fidelity tests, you should run all of the remaining tests using the class driver. If you intend to ship a 3rd-party driver, you should also run a second series of tests using the 3rd-party audio driver.

(Optional) Run fidelity tests using 3rd-party sAPO

If you are employing a 3rd-party Audio Systems Effect, or APO, you should re-run the fidelity tests with your sAPO installed. Test with your processing engaged and disengaged. When the processing is disengaged, the results should be identical to the previous audio fidelity tests. When the processing is engaged, try to interpret the results based on what the processing is designed to accomplish. For instance, if the APO performs equalization on the signal, then it will likely fail the frequency response logo test, depending on the settings of the equalization algorithm in your sAPO. Optimal Sound can perform this testing for you, click here for more information.

Usability testing

While usability testing is always an important concern, it is especially important given all the changes to audio Microsoft Vista, Usability testing is largely an iterative process, and is fundamentally different from functional testing. Usability testing observes how typical users perform critical tasks using the system being tested, then factors corrections into the next development release, where the usability is again tested with a new group of test subjects. Optimal Sound can perform usability testing for you; click here for more information.

For a good overview of simplified usability testing, check out the Great Minds in Development video interview with Steve Krug, author of the book, Don't Make Me Think. Steve's pitch line for simplified usability testing is "Just give me one morning a month..."

Functional testing

Functional testing is the process of determining whether the audio subystem performs as expected. Rather than running a battery of automated tests, functional testers perform common tasks and verify correct results. Unlike usability testing, the same team of functional testers deployed for each successive development release. Functional testing should be employed for each piece of audio-enabled software shipped on a system. For instance, if your system includes a media jukebox program, then both the media jukebox and Windows Media Player should be tested to verify that they both play all popular audio file formats. Optimal Sound can perform audio functional testing for you, click here for more information.

Work with Microsoft to address any remaining barriers to launch

Optimal Sound has a direct relationship with Microsoft, and can help you with resolving issues at Microsoft. There are many different teams involved with Vista audio at Microsoft, and each has their own agenda. Optimal Sound can advise you on how to best approach Microsoft on sensitive issues, or Optimal Sound can represent you directly at Microsoft.

Use Optimal Sound services to add an audio expert to your team, and ensure that your systems sound great, are easy to understand, and function properly with Windows Vista. Contact us for more info.