The Audio Stream Handler is used to control streaming of audio data. In some cases, the Audio Stream Handler acts as a consumer of audio data, and in other cases it acts as a producer. The audio data in each of these cases is always digital. It is sometimes compressed and sometimes uncompressed. Each of these cases is discussed in detail below. In addition to these discussions, information is included concerning interaction between this module and the Sync/Stream Manager.

This module is implemented as a DLL running at Ring 3 as well as a stub device driver module (PDD) running at Ring 0 (system kernel privilege level).

The Audio Stream Handler running at Ring 3 can call Ring 3 DLL audio CODECs to assist in compressing and decompressing audio data. The Ring 3 Audio Stream Handler communicates with audio device drivers through the DDCMD interfaces in the VSD. (Refer to the OS/2 Multimedia Programming Reference for the VSD DDCMD interface definitions.)

Existing audio device drivers use standard audio-device-driver interface (DDCMDs) to communicate with the Ring 0 stub device driver module.

External Interface Description

The description for the Ring 3 Audio Stream Handler external interface follows: