ACX reference documentation

This topic describes the header level reference documentation for the ACX audio class extensions.

For a general overview of ACX, see ACX audio class extensions overview. ACX is based on the Windows Driver Framework (WDF) and WDF reference topics can also be useful when looking at the functions and callbacks in ACX. For more information about WDF see Introduction to Framework Objects.


The ACX headers and libraries are not included in the WDK 10.0.22621.2428 (released October 24, 2023), but are available in previous versions, as well as the latest (25000 series builds) Insider Preview of the WDK. For more information about preview versions of the WDK, see Installing preview versions of the Windows Driver Kit (WDK).

The following ACX headers have reference documentation available.

Just like WDF drivers, DEVICE and DRIVER are used to initialize the base driver.

Pins, streams and circuits are used to route audio signals.

The data formats are controlled using this header.

The acxelements header provides access to specific audio system elements, such as volume, mute, peakmeter and the keyword spotter.

Events and requests allow for notification.

An object bag, which can be used to store and retrieve configuration information and is defined in acxmisc.

The ACX manager is used for supporting composite audio endpoints.

See also

ACX audio class extensions overview

Summary of ACX objects

ACX version information

ACX logging and debugging

ACX targets and driver synchronization

ACX IO request packet IRPs

ACX device enumeration

ACX power management

ACX multi stack cross driver communications

ACX streaming