SYSAUDIO_INSTANCE_INFO structure (ksmedia.h)

The SYSAUDIO_INSTANCE_INFO structure specifies which virtual audio device to open and includes flags for configuring that device.

Syntax

typedef struct {
  KSPROPERTY Property;
  ULONG      Flags;
  ULONG      DeviceNumber;
} SYSAUDIO_INSTANCE_INFO, *PSYSAUDIO_INSTANCE_INFO;

Members

Property

Specifies the property. This parameter is a structure of type KSPROPERTY.

Flags

Flags specifying how to configure the virtual audio device. Currently, the only flag bit defined for this parameter is SYSAUDIO_FLAGS_DONT_COMBINE_PINS. If set, this flag bit instructs SysAudio not to combine rendering pins. For more information, see the following Remarks section.

DeviceNumber

Specifies the device ID. This member identifies the virtual audio device that is to be opened by the property request. If SysAudio enumerates N virtual audio devices (see KSPROPERTY_SYSAUDIO_DEVICE_COUNT), the valid device IDs range from 0 to N-1.

Remarks

This structure is used by the KSPROPERTY_SYSAUDIO_INSTANCE_INFO property.

By default, a virtual audio device combines its wave-rendering pins. The SYSAUDIO_FLAGS_DONT_COMBINE_PINS flag overrides this default.

When pins are combined, the virtual audio device exposes a single pin factory that combines hardware-accelerated rendering pins on the audio device with software-emulated mixer pins on the KMixer system driver. If the pins are not combined, then hardware-accelerated pins and software-emulated pins are exposed through separate pin factories. In order to correctly report the number of hardware-accelerated pins to application programs, DirectSound requires that the pins not be combined.

This property is similar to KSPROPERTY_SYSAUDIO_DEVICE_INSTANCE, with the exception that it includes flags specifying how to configure the virtual audio device.

Requirements

Requirement	Value
Header	ksmedia.h (include Ksmedia.h)

See also

KSPROPERTY

KSPROPERTY_SYSAUDIO_DEVICE_COUNT

KSPROPERTY_SYSAUDIO_DEVICE_INSTANCE

KSPROPERTY_SYSAUDIO_INSTANCE_INFO