DIRECTX_AUDIO_ACTIVATION_PARAMS structure (mmdeviceapi.h)

The DIRECTX_AUDIO_ACTIVATION_PARAMS structure specifies the initialization parameters for a DirectSound stream.

Syntax

typedef struct tagDIRECTX_AUDIO_ACTIVATION_PARAMS {
  DWORD cbDirectXAudioActivationParams;
  GUID  guidAudioSession;
  DWORD dwAudioStreamFlags;
} DIRECTX_AUDIO_ACTIVATION_PARAMS, *PDIRECTX_AUDIO_ACTIVATION_PARAMS;

Members

cbDirectXAudioActivationParams

The size, in bytes, of the DIRECTX_AUDIO_ACTIVATION_PARAMS structure. Set this member to sizeof(DIRECTX_AUDIO_ACTIVATION_PARAMS).

guidAudioSession

Session GUID. This member is a GUID value that identifies the audio session that the stream belongs to. If the GUID identifies a session that has been previously opened, the method adds the stream to that session. If the GUID does not identify an existing session, the method opens a new session and adds the stream to that session. The stream remains a member of the same session for its lifetime.

dwAudioStreamFlags

Stream-initialization flags. This member specifies whether the stream belongs to a cross-process session or to a session that is specific to the current process. Set this member to 0 or to the following AUDCLNT_STREAMFLAGS_XXX constant:

AUDCLNT_STREAMFLAGS_CROSSPROCESS

Remarks

This structure is used by the IMMDevice::Activate method. When activating an IDirectSound, IDirectSoundCapture, or IBaseFilter interface on an audio endpoint device, the DIRECTX_AUDIO_ACTIVATION_PARAMS structure specifies the session GUID and stream-initialization flags for the audio stream that the DirectSound module creates and encapsulates in the interface instance. During the Activate call, DirectSound calls the IAudioClient::Initialize method and specifies the session GUID and stream-initialization flags from the DIRECTX_AUDIO_ACTIVATION_PARAMS structure as input parameters.

For more information about IDirectSound, IDirectSoundCapture, and IBaseFilter, see the Windows SDK documentation.

For a code example that uses the DIRECTX_AUDIO_ACTIVATION_PARAMS structure, see Device Roles for DirectShow Applications.

Requirements

See also

Core Audio Structures

IAudioClient::Initialize

IMMDevice::Activate