Client DLL Shell

The framework includes source code for a DLL shell which hosts your proprietary signal processing algorithm. You implement your source code within this shell DLL, which becomes a part of the driver package.

Command Line Test App

The command line test app is used during development, debugging, and qualification of your propietary algorithm. It reads and writes audio files. This way the Client DLL Shell can be qualified entirely indpendently of the APO run-time environment.

INF Files

INF files are underappreciated yet vital components of the Windows† Audio driver stacks. The INF file is the glue that holds the driver package together. Optimal's INF files support Windows 7, 8, and 8.1, and support 32-bit and 64-bit OSes, all in a single INF file. They can be scoped to a specific range of hardware devices, or opened up to all devices on the bus. Customizations can be added on a per-Plug-And-Play ID basis.

Driver Signing

Windows drivers must be signed in order to function properly, even during the development process. We provide scripts which allow you to test-sign the driver package while in development, and then production-sign the finished package prior to submission to Microsoft WHQL for certification. We also provide the capability to modify and test-sign 3rd party driver packages which are integrating your APO and processing DLL.

Filter Drivers

Optional filter drivers can be deployed to perform advanced functions.

A lower filter driver can intercept the traffic between the audio class driver or audio function driver and modify the calls and responses from the driver to the device. When used on the HD Audio bus, it's possible to modify the HD Audio verb traffic going to the device on a per-node and per-function basis, and it's possible to modify the responses. This is an extemely powerful way to easily extend or modify the functionality of the HD Audio class driver, thus eliminating the need to develop a complete audio function driver.

Our lower filter driver for HD Audio can also be used stand-alone as an HD Audio Bus Traffic Analyzer. It can also analyze traffic calls from the audio function driver into the HD Audio Bus Driver. Output is in the form of .ETL log files, which can be viewed using Perfview or Windows Performance Analyzer.

An upper filter driver can be deployed to provide communications between apps and the lower filter driver, and to intercept and modify traffic from the application layer going in and out of the audio class or function driver.