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.
void SetPreFetchOffset( ULONG PreFetchOffset );
Specifies the prefetch offset size in bytes.
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.
|Header||portcls.h (include Portcls.h)|