IPreFetchOffset::SetPreFetchOffset method (portcls.h)
The SetPreFetchOffset
method sets the prefetch offset, which is the number of bytes of data separating the write cursor from the play cursor in a DirectSound output stream.
Syntax
void SetPreFetchOffset(
[in] ULONG PreFetchOffset
);
Parameters
[in] PreFetchOffset
Specifies the prefetch offset size in bytes.
Return value
None
Remarks
A WavePci miniport driver calls the SetPreFetchOffset
method to specify the prefetch offset of a hardware-accelerated DirectSound output stream.
The prefetch offset is the number of bytes of data separating the write cursor from the play cursor in the audio device's hardware buffer:
- The write cursor specifies the buffer position into which a DirectSound application can safely write the next sound sample.
- The play cursor specifies the buffer position of the sound sample that is currently being played by the audio device.
For information about using SetPreFetchOffset
to control a DirectSound stream's prefetch offset, see Prefetch Offsets.
Requirements
Requirement | Value |
---|---|
Target Platform | Universal |
Header | portcls.h (include Portcls.h) |
IRQL | Any level |
See also
IMiniportWavePciStream::GetPosition