KSPROPERTY_RTAUDIO_PRESENTATION_POSITION

KSPROPERTY_RTAUDIO_PRESENTATION_POSITION returns stream presentation information.

Usage Summary Table

Get	Set	Target	Property descriptor type	Property value type
Yes	No	Pin	KSPROPERTY	KSAUDIO_PRESENTATION_POSITION

The property descriptor (instance data) is a KSPROPERTY structure. Before sending the request, the client loads the structure with values that describe the current cursor position in audio data stream.

The property value is a KSAUDIO_PRESENTATION_POSITION structure that represents a recent presentation position in the audio data stream.

Return Value

A KSPROPERTY_RTAUDIO_PRESENTATION_POSITION property request returns STATUS_SUCCESS to indicate that it has completed successfully. Otherwise, the request returns an appropriate failure status code.

Remarks

The OS may periodically get this property from the driver to retrieve recent presentation position information from the driver in order to allow upper layers to synchronize video or other activity with the audio stream.

The value returned in the u64PositionInBlocks member of KSAUDIO_PRESENTATION_POSITION should be consistent with the packet count returned by KSPROPERTY_RTAUDIO_PACKETCOUNT and the driver’s interpretation of the packet number passed to SetWritePacket. In other words, the first sample of packet 0 is block 0.

This does not mean that KSPROPERTY_RTAUDIO_PACKETCOUNT and KSPROPERTY_RTAUDIO_PRESENTATION_POSITION, if called simultaneously, would return values that refer to the same sample. KSPROPERTY_RTAUDIO_PACKETCOUNT returns information about the samples transferred from the WaveRT buffer to the hardware, while KSPROPERTY_RTAUDIO_PRESENTATION_POSITION returns information about samples presented at the output of the system. These are two different pieces of information.

Requirements

Version	Available in Windows 10 and later Windows operating systems.
Header	Ksmedia.h

See also

KSPROPSETID_RTAudio