IDirectSound Interface Method Groups
Applications use the methods of the IDirectSound interface to create DirectSound objects and set up the environment. The methods can be organized into the following groups:
Allocating memory Compact
Creating buffers CreateSoundBuffer
Device capabilities GetCaps
IUnknown AddRef
Speaker configuration GetSpeakerConfig
All COM interfaces inherit the IUnknown interface methods, which are listed in the "IUnknown" group above. These three methods allow additional interfaces to be added to the DirectSound object without affecting the functionality of the original interface.