The Audio Compression Manager (ACM) provides a set of API functions that allows a client to perform compressions, decompressions, format conversions, and filtering operations on waveform file data.
The ACM is implemented as a dynamic-link library named msacm32.dll. Applications that link with the ACM can call its API functions. The ACM is also used by the Windows NT® wave mapper, msacm32.drv, so applications that specify the wave mapper as an input or output device make indirect use of the ACM. To view a diagram that illustrates the relationship of the ACM to other Windows NT audio software, see Audio Software Components.
Descriptions of the ACM API functions are provided in the Win32 SDK. ACM API functions begin with a prefix of acm.
The ACM calls installable, user-mode drivers to perform conversions. Most ACM drivers can be installed with the Control Panel’s Multimedia applet and are available to all Win32-based applications. (For more information, see Installing Multimedia Drivers.) Individual applications can also load ACM drivers for their own private use. (For more information, see acmDriverAdd in the Win32 SDK, and Designing Local ACM Drivers.)